Add m-esr52 at 52.6.0

11 files changed, 4594 insertions, 0 deletions

diff --git a/browser/components/downloads/content/allDownloadsViewOverlay.js b/browser/components/downloads/content/allDownloadsViewOverlay.js
new file mode 100644
index 000000000..58078cd08
--- /dev/null
+++ b/browser/components/downloads/content/allDownloadsViewOverlay.js
@@ -0,0 +1,1439 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "DownloadUtils",
+                                  "resource://gre/modules/DownloadUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "DownloadsCommon",
+                                  "resource:///modules/DownloadsCommon.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "DownloadsViewUI",
+                                  "resource:///modules/DownloadsViewUI.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "FileUtils",
+                                  "resource://gre/modules/FileUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
+                                  "resource://gre/modules/NetUtil.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "OS",
+                                  "resource://gre/modules/osfile.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
+                                  "resource://gre/modules/PlacesUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Promise",
+                                  "resource://gre/modules/Promise.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "RecentWindow",
+                                  "resource:///modules/RecentWindow.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Services",
+                                  "resource://gre/modules/Services.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Task",
+                                  "resource://gre/modules/Task.jsm");
+
+const nsIDM = Ci.nsIDownloadManager;
+
+const DESTINATION_FILE_URI_ANNO  = "downloads/destinationFileURI";
+const DOWNLOAD_META_DATA_ANNO    = "downloads/metaData";
+
+/**
+ * Represents a download from the browser history. It implements part of the
+ * interface of the Download object.
+ *
+ * @param aPlacesNode
+ *        The Places node from which the history download should be initialized.
+ */
+function HistoryDownload(aPlacesNode) {
+  // TODO (bug 829201): history downloads should get the referrer from Places.
+  this.source = {
+    url: aPlacesNode.uri,
+  };
+  this.target = {
+    path: undefined,
+    exists: false,
+    size: undefined,
+  };
+
+  // In case this download cannot obtain its end time from the Places metadata,
+  // use the time from the Places node, that is the start time of the download.
+  this.endTime = aPlacesNode.time / 1000;
+}
+
+HistoryDownload.prototype = {
+  /**
+   * Pushes information from Places metadata into this object.
+   */
+  updateFromMetaData(metaData) {
+    try {
+      this.target.path = Cc["@mozilla.org/network/protocol;1?name=file"]
+                           .getService(Ci.nsIFileProtocolHandler)
+                           .getFileFromURLSpec(metaData.targetFileSpec).path;
+    } catch (ex) {
+      this.target.path = undefined;
+    }
+
+    if ("state" in metaData) {
+      this.succeeded = metaData.state == nsIDM.DOWNLOAD_FINISHED;
+      this.canceled = metaData.state == nsIDM.DOWNLOAD_CANCELED ||
+                      metaData.state == nsIDM.DOWNLOAD_PAUSED;
+      this.endTime = metaData.endTime;
+
+      // Recreate partial error information from the state saved in history.
+      if (metaData.state == nsIDM.DOWNLOAD_FAILED) {
+        this.error = { message: "History download failed." };
+      } else if (metaData.state == nsIDM.DOWNLOAD_BLOCKED_PARENTAL) {
+        this.error = { becauseBlockedByParentalControls: true };
+      } else if (metaData.state == nsIDM.DOWNLOAD_DIRTY) {
+        this.error = {
+          becauseBlockedByReputationCheck: true,
+          reputationCheckVerdict: metaData.reputationCheckVerdict || "",
+        };
+      } else {
+        this.error = null;
+      }
+
+      // Normal history downloads are assumed to exist until the user interface
+      // is refreshed, at which point these values may be updated.
+      this.target.exists = true;
+      this.target.size = metaData.fileSize;
+    } else {
+      // Metadata might be missing from a download that has started but hasn't
+      // stopped already. Normally, this state is overridden with the one from
+      // the corresponding in-progress session download. But if the browser is
+      // terminated abruptly and additionally the file with information about
+      // in-progress downloads is lost, we may end up using this state. We use
+      // the failed state to allow the download to be restarted.
+      //
+      // On the other hand, if the download is missing the target file
+      // annotation as well, it is just a very old one, and we can assume it
+      // succeeded.
+      this.succeeded = !this.target.path;
+      this.error = this.target.path ? { message: "Unstarted download." } : null;
+      this.canceled = false;
+
+      // These properties may be updated if the user interface is refreshed.
+      this.target.exists = false;
+      this.target.size = undefined;
+    }
+  },
+
+  /**
+   * History downloads are never in progress.
+   */
+  stopped: true,
+
+  /**
+   * No percentage indication is shown for history downloads.
+   */
+  hasProgress: false,
+
+  /**
+   * History downloads cannot be restarted using their partial data, even if
+   * they are indicated as paused in their Places metadata. The only way is to
+   * use the information from a persisted session download, that will be shown
+   * instead of the history download. In case this session download is not
+   * available, we show the history download as canceled, not paused.
+   */
+  hasPartialData: false,
+
+  /**
+   * This method mimicks the "start" method of session downloads, and is called
+   * when the user retries a history download.
+   *
+   * At present, we always ask the user for a new target path when retrying a
+   * history download. In the future we may consider reusing the known target
+   * path if the folder still exists and the file name is not already used,
+   * except when the user preferences indicate that the target path should be
+   * requested every time a new download is started.
+   */
+  start() {
+    let browserWin = RecentWindow.getMostRecentBrowserWindow();
+    let initiatingDoc = browserWin ? browserWin.document : document;
+
+    // Do not suggest a file name if we don't know the original target.
+    let leafName = this.target.path ? OS.Path.basename(this.target.path) : null;
+    DownloadURL(this.source.url, leafName, initiatingDoc);
+
+    return Promise.resolve();
+  },
+
+  /**
+   * This method mimicks the "refresh" method of session downloads, except that
+   * it cannot notify that the data changed to the Downloads View.
+   */
+  refresh: Task.async(function* () {
+    try {
+      this.target.size = (yield OS.File.stat(this.target.path)).size;
+      this.target.exists = true;
+    } catch (ex) {
+      // We keep the known file size from the metadata, if any.
+      this.target.exists = false;
+    }
+  }),
+};
+
+/**
+ * A download element shell is responsible for handling the commands and the
+ * displayed data for a single download view element.
+ *
+ * The shell may contain a session download, a history download, or both.  When
+ * both a history and a session download are present, the session download gets
+ * priority and its information is displayed.
+ *
+ * On construction, a new richlistitem is created, and can be accessed through
+ * the |element| getter. The shell doesn't insert the item in a richlistbox, the
+ * caller must do it and remove the element when it's no longer needed.
+ *
+ * The caller is also responsible for forwarding status notifications for
+ * session downloads, calling the onStateChanged and onChanged methods.
+ *
+ * @param [optional] aSessionDownload
+ *        The session download, required if aHistoryDownload is not set.
+ * @param [optional] aHistoryDownload
+ *        The history download, required if aSessionDownload is not set.
+ */
+function HistoryDownloadElementShell(aSessionDownload, aHistoryDownload) {
+  this.element = document.createElement("richlistitem");
+  this.element._shell = this;
+
+  this.element.classList.add("download");
+  this.element.classList.add("download-state");
+
+  if (aSessionDownload) {
+    this.sessionDownload = aSessionDownload;
+  }
+  if (aHistoryDownload) {
+    this.historyDownload = aHistoryDownload;
+  }
+}
+
+HistoryDownloadElementShell.prototype = {
+  __proto__: DownloadsViewUI.DownloadElementShell.prototype,
+
+  /**
+   * Manages the "active" state of the shell.  By default all the shells without
+   * a session download are inactive, thus their UI is not updated.  They must
+   * be activated when entering the visible area.  Session downloads are always
+   * active.
+   */
+  ensureActive() {
+    if (!this._active) {
+      this._active = true;
+      this.element.setAttribute("active", true);
+      this._updateUI();
+    }
+  },
+  get active() {
+    return !!this._active;
+  },
+
+  /**
+   * Overrides the base getter to return the Download or HistoryDownload object
+   * for displaying information and executing commands in the user interface.
+   */
+  get download() {
+    return this._sessionDownload || this._historyDownload;
+  },
+
+  _sessionDownload: null,
+  get sessionDownload() {
+    return this._sessionDownload;
+  },
+  set sessionDownload(aValue) {
+    if (this._sessionDownload != aValue) {
+      if (!aValue && !this._historyDownload) {
+        throw new Error("Should always have either a Download or a HistoryDownload");
+      }
+
+      this._sessionDownload = aValue;
+
+      this.ensureActive();
+      this._updateUI();
+    }
+    return aValue;
+  },
+
+  _historyDownload: null,
+  get historyDownload() {
+    return this._historyDownload;
+  },
+  set historyDownload(aValue) {
+    if (this._historyDownload != aValue) {
+      if (!aValue && !this._sessionDownload) {
+        throw new Error("Should always have either a Download or a HistoryDownload");
+      }
+
+      this._historyDownload = aValue;
+
+      // We don't need to update the UI if we had a session data item, because
+      // the places information isn't used in this case.
+      if (!this._sessionDownload) {
+        this._updateUI();
+      }
+    }
+    return aValue;
+  },
+
+  _updateUI() {
+    // There is nothing to do if the item has always been invisible.
+    if (!this.active) {
+      return;
+    }
+
+    // Since the state changed, we may need to check the target file again.
+    this._targetFileChecked = false;
+
+    this._updateState();
+  },
+
+  get statusTextAndTip() {
+    let status = this.rawStatusTextAndTip;
+
+    // The base object would show extended progress information in the tooltip,
+    // but we move this to the main view and never display a tooltip.
+    if (!this.download.stopped) {
+      status.text = status.tip;
+    }
+    status.tip = "";
+
+    return status;
+  },
+
+  onStateChanged() {
+    this._updateState();
+
+    if (this.element.selected) {
+      goUpdateDownloadCommands();
+    } else {
+      // If a state change occurs in an item that is not currently selected,
+      // this is the only command that may be affected.
+      goUpdateCommand("downloadsCmd_clearDownloads");
+    }
+  },
+
+  onChanged() {
+    // This cannot be placed within onStateChanged because
+    // when a download goes from hasBlockedData to !hasBlockedData
+    // it will still remain in the same state.
+    this.element.classList.toggle("temporary-block",
+                                  !!this.download.hasBlockedData);
+    this._updateProgress();
+  },
+
+  isCommandEnabled(aCommand) {
+    // The only valid command for inactive elements is cmd_delete.
+    if (!this.active && aCommand != "cmd_delete") {
+      return false;
+    }
+    switch (aCommand) {
+      case "downloadsCmd_open":
+        // This property is false if the download did not succeed.
+        return this.download.target.exists;
+      case "downloadsCmd_show":
+        // TODO: Bug 827010 - Handle part-file asynchronously.
+        if (this._sessionDownload && this.download.target.partFilePath) {
+          let partFile = new FileUtils.File(this.download.target.partFilePath);
+          if (partFile.exists()) {
+            return true;
+          }
+        }
+
+        // This property is false if the download did not succeed.
+        return this.download.target.exists;
+      case "cmd_delete":
+        // We don't want in-progress downloads to be removed accidentally.
+        return this.download.stopped;
+      case "downloadsCmd_cancel":
+        return !!this._sessionDownload;
+    }
+    return DownloadsViewUI.DownloadElementShell.prototype
+                          .isCommandEnabled.call(this, aCommand);
+  },
+
+  doCommand(aCommand) {
+    if (DownloadsViewUI.isCommandName(aCommand)) {
+      this[aCommand]();
+    }
+  },
+
+  downloadsCmd_open() {
+    let file = new FileUtils.File(this.download.target.path);
+    DownloadsCommon.openDownloadedFile(file, null, window);
+  },
+
+  downloadsCmd_show() {
+    let file = new FileUtils.File(this.download.target.path);
+    DownloadsCommon.showDownloadedFile(file);
+  },
+
+  downloadsCmd_openReferrer() {
+    openURL(this.download.source.referrer);
+  },
+
+  cmd_delete() {
+    if (this._sessionDownload) {
+      DownloadsCommon.removeAndFinalizeDownload(this.download);
+    }
+    if (this._historyDownload) {
+      let uri = NetUtil.newURI(this.download.source.url);
+      PlacesUtils.bhistory.removePage(uri);
+    }
+  },
+
+  downloadsCmd_unblock() {
+    this.confirmUnblock(window, "unblock");
+  },
+
+  downloadsCmd_chooseUnblock() {
+    this.confirmUnblock(window, "chooseUnblock");
+  },
+
+  downloadsCmd_chooseOpen() {
+    this.confirmUnblock(window, "chooseOpen");
+  },
+
+  // Returns whether or not the download handled by this shell should
+  // show up in the search results for the given term.  Both the display
+  // name for the download and the url are searched.
+  matchesSearchTerm(aTerm) {
+    if (!aTerm) {
+      return true;
+    }
+    aTerm = aTerm.toLowerCase();
+    return this.displayName.toLowerCase().includes(aTerm) ||
+           this.download.source.url.toLowerCase().includes(aTerm);
+  },
+
+  // Handles return keypress on the element (the keypress listener is
+  // set in the DownloadsPlacesView object).
+  doDefaultCommand() {
+    let command = this.currentDefaultCommandName;
+    if (command && this.isCommandEnabled(command)) {
+      this.doCommand(command);
+    }
+  },
+
+  /**
+   * This method is called by the outer download view, after the controller
+   * commands have already been updated. In case we did not check for the
+   * existence of the target file already, we can do it now and then update
+   * the commands as needed.
+   */
+  onSelect() {
+    if (!this.active) {
+      return;
+    }
+
+    // If this is a history download for which no target file information is
+    // available, we cannot retrieve information about the target file.
+    if (!this.download.target.path) {
+      return;
+    }
+
+    // Start checking for existence.  This may be done twice if onSelect is
+    // called again before the information is collected.
+    if (!this._targetFileChecked) {
+      this._checkTargetFileOnSelect().catch(Cu.reportError);
+    }
+  },
+
+  _checkTargetFileOnSelect: Task.async(function* () {
+    try {
+      yield this.download.refresh();
+    } finally {
+      // Do not try to check for existence again if this failed once.
+      this._targetFileChecked = true;
+    }
+
+    // Update the commands only if the element is still selected.
+    if (this.element.selected) {
+      goUpdateDownloadCommands();
+    }
+
+    // Ensure the interface has been updated based on the new values. We need to
+    // do this because history downloads can't trigger update notifications.
+    this._updateProgress();
+  }),
+};
+
+/**
+ * Relays commands from the download.xml binding to the selected items.
+ */
+const DownloadsView = {
+  onDownloadCommand(event, command) {
+    goDoCommand(command);
+  },
+
+  onDownloadClick() {},
+};
+
+/**
+ * A Downloads Places View is a places view designed to show a places query
+ * for history downloads alongside the session downloads.
+ *
+ * As we don't use the places controller, some methods implemented by other
+ * places views are not implemented by this view.
+ *
+ * A richlistitem in this view can represent either a past download or a session
+ * download, or both. Session downloads are shown first in the view, and as long
+ * as they exist they "collapses" their history "counterpart" (So we don't show two
+ * items for every download).
+ */
+function DownloadsPlacesView(aRichListBox, aActive = true) {
+  this._richlistbox = aRichListBox;
+  this._richlistbox._placesView = this;
+  window.controllers.insertControllerAt(0, this);
+
+  // Map download URLs to download element shells regardless of their type
+  this._downloadElementsShellsForURI = new Map();
+
+  // Map download data items to their element shells.
+  this._viewItemsForDownloads = new WeakMap();
+
+  // Points to the last session download element. We keep track of this
+  // in order to keep all session downloads above past downloads.
+  this._lastSessionDownloadElement = null;
+
+  this._searchTerm = "";
+
+  this._active = aActive;
+
+  // Register as a downloads view. The places data will be initialized by
+  // the places setter.
+  this._initiallySelectedElement = null;
+  this._downloadsData = DownloadsCommon.getData(window.opener || window);
+  this._downloadsData.addView(this);
+
+  // Get the Download button out of the attention state since we're about to
+  // view all downloads.
+  DownloadsCommon.getIndicatorData(window).attention = DownloadsCommon.ATTENTION_NONE;
+
+  // Make sure to unregister the view if the window is closed.
+  window.addEventListener("unload", () => {
+    window.controllers.removeController(this);
+    this._downloadsData.removeView(this);
+    this.result = null;
+  }, true);
+  // Resizing the window may change items visibility.
+  window.addEventListener("resize", () => {
+    this._ensureVisibleElementsAreActive();
+  }, true);
+}
+
+DownloadsPlacesView.prototype = {
+  get associatedElement() {
+    return this._richlistbox;
+  },
+
+  get active() {
+    return this._active;
+  },
+  set active(val) {
+    this._active = val;
+    if (this._active)
+      this._ensureVisibleElementsAreActive();
+    return this._active;
+  },
+
+  /**
+   * This cache exists in order to optimize the load of the Downloads View, when
+   * Places annotations for history downloads must be read. In fact, annotations
+   * are stored in a single table, and reading all of them at once is much more
+   * efficient than an individual query.
+   *
+   * When this property is first requested, it reads the annotations for all the
+   * history downloads and stores them indefinitely.
+   *
+   * The historical annotations are not expected to change for the duration of
+   * the session, except in the case where a session download is running for the
+   * same URI as a history download. To ensure we don't use stale data, URIs
+   * corresponding to session downloads are permanently removed from the cache.
+   * This is a very small mumber compared to history downloads.
+   *
+   * This property returns a Map from each download source URI found in Places
+   * annotations to an object with the format:
+   *
+   * { targetFileSpec, state, endTime, fileSize, ... }
+   *
+   * The targetFileSpec property is the value of "downloads/destinationFileURI",
+   * while the other properties are taken from "downloads/metaData". Any of the
+   * properties may be missing from the object.
+   */
+  get _cachedPlacesMetaData() {
+    if (!this.__cachedPlacesMetaData) {
+      this.__cachedPlacesMetaData = new Map();
+
+      // Read the metadata annotations first, but ignore invalid JSON.
+      for (let result of PlacesUtils.annotations.getAnnotationsWithName(
+                                                 DOWNLOAD_META_DATA_ANNO)) {
+        try {
+          this.__cachedPlacesMetaData.set(result.uri.spec,
+                                          JSON.parse(result.annotationValue));
+        } catch (ex) {}
+      }
+
+      // Add the target file annotations to the metadata.
+      for (let result of PlacesUtils.annotations.getAnnotationsWithName(
+                                                 DESTINATION_FILE_URI_ANNO)) {
+        let metaData = this.__cachedPlacesMetaData.get(result.uri.spec);
+        if (!metaData) {
+          metaData = {};
+          this.__cachedPlacesMetaData.set(result.uri.spec, metaData);
+        }
+        metaData.targetFileSpec = result.annotationValue;
+      }
+    }
+
+    return this.__cachedPlacesMetaData;
+  },
+  __cachedPlacesMetaData: null,
+
+  /**
+   * Reads current metadata from Places annotations for the specified URI, and
+   * returns an object with the format:
+   *
+   * { targetFileSpec, state, endTime, fileSize, ... }
+   *
+   * The targetFileSpec property is the value of "downloads/destinationFileURI",
+   * while the other properties are taken from "downloads/metaData". Any of the
+   * properties may be missing from the object.
+   */
+  _getPlacesMetaDataFor(spec) {
+    let metaData = {};
+
+    try {
+      let uri = NetUtil.newURI(spec);
+      try {
+        metaData = JSON.parse(PlacesUtils.annotations.getPageAnnotation(
+                                          uri, DOWNLOAD_META_DATA_ANNO));
+      } catch (ex) {}
+      metaData.targetFileSpec = PlacesUtils.annotations.getPageAnnotation(
+                                            uri, DESTINATION_FILE_URI_ANNO);
+    } catch (ex) {}
+
+    return metaData;
+  },
+
+  /**
+   * Given a data item for a session download, or a places node for a past
+   * download, updates the view as necessary.
+   *  1. If the given data is a places node, we check whether there are any
+   *     elements for the same download url. If there are, then we just reset
+   *     their places node. Otherwise we add a new download element.
+   *  2. If the given data is a data item, we first check if there's a history
+   *     download in the list that is not associated with a data item. If we
+   *     found one, we use it for the data item as well and reposition it
+   *     alongside the other session downloads. If we don't, then we go ahead
+   *     and create a new element for the download.
+   *
+   * @param [optional] sessionDownload
+   *        A Download object, or null for history downloads.
+   * @param [optional] aPlacesNode
+   *        The Places node for a history download, or null for session downloads.
+   * @param [optional] aNewest
+   *        @see onDownloadAdded. Ignored for history downloads.
+   * @param [optional] aDocumentFragment
+   *        To speed up the appending of multiple elements to the end of the
+   *        list which are coming in a single batch (i.e. invalidateContainer),
+   *        a document fragment may be passed to which the new elements would
+   *        be appended. It's the caller's job to ensure the fragment is merged
+   *        to the richlistbox at the end.
+   */
+  _addDownloadData(sessionDownload, aPlacesNode, aNewest = false,
+                   aDocumentFragment = null) {
+    let downloadURI = aPlacesNode ? aPlacesNode.uri
+                                  : sessionDownload.source.url;
+    let shellsForURI = this._downloadElementsShellsForURI.get(downloadURI);
+    if (!shellsForURI) {
+      shellsForURI = new Set();
+      this._downloadElementsShellsForURI.set(downloadURI, shellsForURI);
+    }
+
+    // When a session download is attached to a shell, we ensure not to keep
+    // stale metadata around for the corresponding history download. This
+    // prevents stale state from being used if the view is rebuilt.
+    //
+    // Note that we will eagerly load the data in the cache at this point, even
+    // if we have seen no history download. The case where no history download
+    // will appear at all is rare enough in normal usage, so we can apply this
+    // simpler solution rather than keeping a list of cache items to ignore.
+    if (sessionDownload) {
+      this._cachedPlacesMetaData.delete(sessionDownload.source.url);
+    }
+
+    let newOrUpdatedShell = null;
+
+    // Trivial: if there are no shells for this download URI, we always
+    // need to create one.
+    let shouldCreateShell = shellsForURI.size == 0;
+
+    // However, if we do have shells for this download uri, there are
+    // few options:
+    // 1) There's only one shell and it's for a history download (it has
+    //    no data item). In this case, we update this shell and move it
+    //    if necessary
+    // 2) There are multiple shells, indicating multiple downloads for
+    //    the same download uri are running. In this case we create
+    //    another shell for the download (so we have one shell for each data
+    //    item).
+    //
+    // Note: If a cancelled session download is already in the list, and the
+    // download is retried, onDownloadAdded is called again for the same
+    // data item. Thus, we also check that we make sure we don't have a view item
+    // already.
+    if (!shouldCreateShell &&
+        sessionDownload && !this._viewItemsForDownloads.has(sessionDownload)) {
+      // If there's a past-download-only shell for this download-uri with no
+      // associated data item, use it for the new data item. Otherwise, go ahead
+      // and create another shell.
+      shouldCreateShell = true;
+      for (let shell of shellsForURI) {
+        if (!shell.sessionDownload) {
+          shouldCreateShell = false;
+          shell.sessionDownload = sessionDownload;
+          newOrUpdatedShell = shell;
+          this._viewItemsForDownloads.set(sessionDownload, shell);
+          break;
+        }
+      }
+    }
+
+    if (shouldCreateShell) {
+      // If we are adding a new history download here, it means there is no
+      // associated session download, thus we must read the Places metadata,
+      // because it will not be obscured by the session download.
+      let historyDownload = null;
+      if (aPlacesNode) {
+        let metaData = this._cachedPlacesMetaData.get(aPlacesNode.uri) ||
+                       this._getPlacesMetaDataFor(aPlacesNode.uri);
+        historyDownload = new HistoryDownload(aPlacesNode);
+        historyDownload.updateFromMetaData(metaData);
+      }
+      let shell = new HistoryDownloadElementShell(sessionDownload,
+                                                  historyDownload);
+      shell.element._placesNode = aPlacesNode;
+      newOrUpdatedShell = shell;
+      shellsForURI.add(shell);
+      if (sessionDownload) {
+        this._viewItemsForDownloads.set(sessionDownload, shell);
+      }
+    } else if (aPlacesNode) {
+      // We are updating information for a history download for which we have
+      // at least one download element shell already. There are two cases:
+      // 1) There are one or more download element shells for this source URI,
+      //    each with an associated session download. We update the Places node
+      //    because we may need it later, but we don't need to read the Places
+      //    metadata until the last session download is removed.
+      // 2) Occasionally, we may receive a duplicate notification for a history
+      //    download with no associated session download. We have exactly one
+      //    download element shell in this case, but the metdata cannot have
+      //    changed, just the reference to the Places node object is different.
+      // So, we update all the node references and keep the metadata intact.
+      for (let shell of shellsForURI) {
+        if (!shell.historyDownload) {
+          // Create the element to host the metadata when needed.
+          shell.historyDownload = new HistoryDownload(aPlacesNode);
+        }
+        shell.element._placesNode = aPlacesNode;
+      }
+    }
+
+    if (newOrUpdatedShell) {
+      if (aNewest) {
+        this._richlistbox.insertBefore(newOrUpdatedShell.element,
+                                       this._richlistbox.firstChild);
+        if (!this._lastSessionDownloadElement) {
+          this._lastSessionDownloadElement = newOrUpdatedShell.element;
+        }
+        // Some operations like retrying an history download move an element to
+        // the top of the richlistbox, along with other session downloads.
+        // More generally, if a new download is added, should be made visible.
+        this._richlistbox.ensureElementIsVisible(newOrUpdatedShell.element);
+      } else if (sessionDownload) {
+        let before = this._lastSessionDownloadElement ?
+          this._lastSessionDownloadElement.nextSibling : this._richlistbox.firstChild;
+        this._richlistbox.insertBefore(newOrUpdatedShell.element, before);
+        this._lastSessionDownloadElement = newOrUpdatedShell.element;
+      } else {
+        let appendTo = aDocumentFragment || this._richlistbox;
+        appendTo.appendChild(newOrUpdatedShell.element);
+      }
+
+      if (this.searchTerm) {
+        newOrUpdatedShell.element.hidden =
+          !newOrUpdatedShell.element._shell.matchesSearchTerm(this.searchTerm);
+      }
+    }
+
+    // If aDocumentFragment is defined this is a batch change, so it's up to
+    // the caller to append the fragment and activate the visible shells.
+    if (!aDocumentFragment) {
+      this._ensureVisibleElementsAreActive();
+      goUpdateCommand("downloadsCmd_clearDownloads");
+    }
+  },
+
+  _removeElement(aElement) {
+    // If the element was selected exclusively, select its next
+    // sibling first, if not, try for previous sibling, if any.
+    if ((aElement.nextSibling || aElement.previousSibling) &&
+        this._richlistbox.selectedItems &&
+        this._richlistbox.selectedItems.length == 1 &&
+        this._richlistbox.selectedItems[0] == aElement) {
+      this._richlistbox.selectItem(aElement.nextSibling ||
+                                   aElement.previousSibling);
+    }
+
+    if (this._lastSessionDownloadElement == aElement) {
+      this._lastSessionDownloadElement = aElement.previousSibling;
+    }
+
+    this._richlistbox.removeItemFromSelection(aElement);
+    this._richlistbox.removeChild(aElement);
+    this._ensureVisibleElementsAreActive();
+    goUpdateCommand("downloadsCmd_clearDownloads");
+  },
+
+  _removeHistoryDownloadFromView(aPlacesNode) {
+    let downloadURI = aPlacesNode.uri;
+    let shellsForURI = this._downloadElementsShellsForURI.get(downloadURI);
+    if (shellsForURI) {
+      for (let shell of shellsForURI) {
+        if (shell.sessionDownload) {
+          shell.historyDownload = null;
+        } else {
+          this._removeElement(shell.element);
+          shellsForURI.delete(shell);
+          if (shellsForURI.size == 0)
+            this._downloadElementsShellsForURI.delete(downloadURI);
+        }
+      }
+    }
+  },
+
+  _removeSessionDownloadFromView(download) {
+    let shells = this._downloadElementsShellsForURI
+                     .get(download.source.url);
+    if (shells.size == 0) {
+      throw new Error("Should have had at leaat one shell for this uri");
+    }
+
+    let shell = this._viewItemsForDownloads.get(download);
+    if (!shells.has(shell)) {
+      throw new Error("Missing download element shell in shells list for url");
+    }
+
+    // If there's more than one item for this download uri, we can let the
+    // view item for this this particular data item go away.
+    // If there's only one item for this download uri, we should only
+    // keep it if it is associated with a history download.
+    if (shells.size > 1 || !shell.historyDownload) {
+      this._removeElement(shell.element);
+      shells.delete(shell);
+      if (shells.size == 0) {
+        this._downloadElementsShellsForURI.delete(download.source.url);
+      }
+    } else {
+      // We have one download element shell containing both a session download
+      // and a history download, and we are now removing the session download.
+      // Previously, we did not use the Places metadata because it was obscured
+      // by the session download. Since this is no longer the case, we have to
+      // read the latest metadata before removing the session download.
+      let url = shell.historyDownload.source.url;
+      let metaData = this._getPlacesMetaDataFor(url);
+      shell.historyDownload.updateFromMetaData(metaData);
+      shell.sessionDownload = null;
+      // Move it below the session-download items;
+      if (this._lastSessionDownloadElement == shell.element) {
+        this._lastSessionDownloadElement = shell.element.previousSibling;
+      } else {
+        let before = this._lastSessionDownloadElement ?
+          this._lastSessionDownloadElement.nextSibling : this._richlistbox.firstChild;
+        this._richlistbox.insertBefore(shell.element, before);
+      }
+    }
+  },
+
+  _ensureVisibleElementsAreActive() {
+    if (!this.active || this._ensureVisibleTimer ||
+        !this._richlistbox.firstChild) {
+      return;
+    }
+
+    this._ensureVisibleTimer = setTimeout(() => {
+      delete this._ensureVisibleTimer;
+      if (!this._richlistbox.firstChild) {
+        return;
+      }
+
+      let rlbRect = this._richlistbox.getBoundingClientRect();
+      let winUtils = window.QueryInterface(Ci.nsIInterfaceRequestor)
+                           .getInterface(Ci.nsIDOMWindowUtils);
+      let nodes = winUtils.nodesFromRect(rlbRect.left, rlbRect.top,
+                                         0, rlbRect.width, rlbRect.height, 0,
+                                         true, false);
+      // nodesFromRect returns nodes in z-index order, and for the same z-index
+      // sorts them in inverted DOM order, thus starting from the one that would
+      // be on top.
+      let firstVisibleNode, lastVisibleNode;
+      for (let node of nodes) {
+        if (node.localName === "richlistitem" && node._shell) {
+          node._shell.ensureActive();
+          // The first visible node is the last match.
+          firstVisibleNode = node;
+          // While the last visible node is the first match.
+          if (!lastVisibleNode) {
+            lastVisibleNode = node;
+          }
+        }
+      }
+
+      // Also activate the first invisible nodes in both boundaries (that is,
+      // above and below the visible area) to ensure proper keyboard navigation
+      // in both directions.
+      let nodeBelowVisibleArea = lastVisibleNode && lastVisibleNode.nextSibling;
+      if (nodeBelowVisibleArea && nodeBelowVisibleArea._shell) {
+        nodeBelowVisibleArea._shell.ensureActive();
+      }
+
+      let nodeAboveVisibleArea = firstVisibleNode &&
+                                 firstVisibleNode.previousSibling;
+      if (nodeAboveVisibleArea && nodeAboveVisibleArea._shell) {
+        nodeAboveVisibleArea._shell.ensureActive();
+      }
+    }, 10);
+  },
+
+  _place: "",
+  get place() {
+    return this._place;
+  },
+  set place(val) {
+    // Don't reload everything if we don't have to.
+    if (this._place == val) {
+      // XXXmano: places.js relies on this behavior (see Bug 822203).
+      this.searchTerm = "";
+      return val;
+    }
+
+    this._place = val;
+
+    let history = PlacesUtils.history;
+    let queries = { }, options = { };
+    history.queryStringToQueries(val, queries, { }, options);
+    if (!queries.value.length) {
+      queries.value = [history.getNewQuery()];
+    }
+
+    let result = history.executeQueries(queries.value, queries.value.length,
+                                        options.value);
+    result.addObserver(this, false);
+    return val;
+  },
+
+  _result: null,
+  get result() {
+    return this._result;
+  },
+  set result(val) {
+    if (this._result == val) {
+      return val;
+    }
+
+    if (this._result) {
+      this._result.removeObserver(this);
+      this._resultNode.containerOpen = false;
+    }
+
+    if (val) {
+      this._result = val;
+      this._resultNode = val.root;
+      this._resultNode.containerOpen = true;
+      this._ensureInitialSelection();
+    } else {
+      delete this._resultNode;
+      delete this._result;
+    }
+
+    return val;
+  },
+
+  get selectedNodes() {
+    return [for (element of this._richlistbox.selectedItems)
+            if (element._placesNode)
+            element._placesNode];
+  },
+
+  get selectedNode() {
+    let selectedNodes = this.selectedNodes;
+    return selectedNodes.length == 1 ? selectedNodes[0] : null;
+  },
+
+  get hasSelection() {
+    return this.selectedNodes.length > 0;
+  },
+
+  containerStateChanged(aNode, aOldState, aNewState) {
+    this.invalidateContainer(aNode)
+  },
+
+  invalidateContainer(aContainer) {
+    if (aContainer != this._resultNode) {
+      throw new Error("Unexpected container node");
+    }
+    if (!aContainer.containerOpen) {
+      throw new Error("Root container for the downloads query cannot be closed");
+    }
+
+    let suppressOnSelect = this._richlistbox.suppressOnSelect;
+    this._richlistbox.suppressOnSelect = true;
+    try {
+      // Remove the invalidated history downloads from the list and unset the
+      // places node for data downloads.
+      // Loop backwards since _removeHistoryDownloadFromView may removeChild().
+      for (let i = this._richlistbox.childNodes.length - 1; i >= 0; --i) {
+        let element = this._richlistbox.childNodes[i];
+        if (element._placesNode) {
+          this._removeHistoryDownloadFromView(element._placesNode);
+        }
+      }
+    } finally {
+      this._richlistbox.suppressOnSelect = suppressOnSelect;
+    }
+
+    if (aContainer.childCount > 0) {
+      let elementsToAppendFragment = document.createDocumentFragment();
+      for (let i = 0; i < aContainer.childCount; i++) {
+        try {
+          this._addDownloadData(null, aContainer.getChild(i), false,
+                                elementsToAppendFragment);
+        } catch (ex) {
+          Cu.reportError(ex);
+        }
+      }
+
+      // _addDownloadData may not add new elements if there were already
+      // data items in place.
+      if (elementsToAppendFragment.firstChild) {
+        this._appendDownloadsFragment(elementsToAppendFragment);
+        this._ensureVisibleElementsAreActive();
+      }
+    }
+
+    goUpdateDownloadCommands();
+  },
+
+  _appendDownloadsFragment(aDOMFragment) {
+    // Workaround multiple reflows hang by removing the richlistbox
+    // and adding it back when we're done.
+
+    // Hack for bug 836283: reset xbl fields to their old values after the
+    // binding is reattached to avoid breaking the selection state
+    let xblFields = new Map();
+    for (let key of Object.getOwnPropertyNames(this._richlistbox)) {
+      let value = this._richlistbox[key];
+      xblFields.set(key, value);
+    }
+
+    let parentNode = this._richlistbox.parentNode;
+    let nextSibling = this._richlistbox.nextSibling;
+    parentNode.removeChild(this._richlistbox);
+    this._richlistbox.appendChild(aDOMFragment);
+    parentNode.insertBefore(this._richlistbox, nextSibling);
+
+    for (let [key, value] of xblFields) {
+      this._richlistbox[key] = value;
+    }
+  },
+
+  nodeInserted(aParent, aPlacesNode) {
+    this._addDownloadData(null, aPlacesNode);
+  },
+
+  nodeRemoved(aParent, aPlacesNode, aOldIndex) {
+    this._removeHistoryDownloadFromView(aPlacesNode);
+  },
+
+  nodeAnnotationChanged() {},
+  nodeIconChanged() {},
+  nodeTitleChanged() {},
+  nodeKeywordChanged() {},
+  nodeDateAddedChanged() {},
+  nodeLastModifiedChanged() {},
+  nodeHistoryDetailsChanged() {},
+  nodeTagsChanged() {},
+  sortingChanged() {},
+  nodeMoved() {},
+  nodeURIChanged() {},
+  batching() {},
+
+  get controller() {
+    return this._richlistbox.controller;
+  },
+
+  get searchTerm() {
+    return this._searchTerm;
+  },
+  set searchTerm(aValue) {
+    if (this._searchTerm != aValue) {
+      for (let element of this._richlistbox.childNodes) {
+        element.hidden = !element._shell.matchesSearchTerm(aValue);
+      }
+      this._ensureVisibleElementsAreActive();
+    }
+    return this._searchTerm = aValue;
+  },
+
+  /**
+   * When the view loads, we want to select the first item.
+   * However, because session downloads, for which the data is loaded
+   * asynchronously, always come first in the list, and because the list
+   * may (or may not) already contain history downloads at that point, it
+   * turns out that by the time we can select the first item, the user may
+   * have already started using the view.
+   * To make things even more complicated, in other cases, the places data
+   * may be loaded after the session downloads data.  Thus we cannot rely on
+   * the order in which the data comes in.
+   * We work around this by attempting to select the first element twice,
+   * once after the places data is loaded and once when the session downloads
+   * data is done loading.  However, if the selection has changed in-between,
+   * we assume the user has already started using the view and give up.
+   */
+  _ensureInitialSelection() {
+    // Either they're both null, or the selection has not changed in between.
+    if (this._richlistbox.selectedItem == this._initiallySelectedElement) {
+      let firstDownloadElement = this._richlistbox.firstChild;
+      if (firstDownloadElement != this._initiallySelectedElement) {
+        // We may be called before _ensureVisibleElementsAreActive,
+        // or before the download binding is attached. Therefore, ensure the
+        // first item is activated, and pass the item to the richlistbox
+        // setters only at a point we know for sure the binding is attached.
+        firstDownloadElement._shell.ensureActive();
+        Services.tm.mainThread.dispatch(() => {
+          this._richlistbox.selectedItem = firstDownloadElement;
+          this._richlistbox.currentItem = firstDownloadElement;
+          this._initiallySelectedElement = firstDownloadElement;
+        }, Ci.nsIThread.DISPATCH_NORMAL);
+      }
+    }
+  },
+
+  onDataLoadStarting() {},
+  onDataLoadCompleted() {
+    this._ensureInitialSelection();
+  },
+
+  onDownloadAdded(download, newest) {
+    this._addDownloadData(download, null, newest);
+  },
+
+  onDownloadStateChanged(download) {
+    this._viewItemsForDownloads.get(download).onStateChanged();
+  },
+
+  onDownloadChanged(download) {
+    this._viewItemsForDownloads.get(download).onChanged();
+  },
+
+  onDownloadRemoved(download) {
+    this._removeSessionDownloadFromView(download);
+  },
+
+  // nsIController
+  supportsCommand(aCommand) {
+    // Firstly, determine if this is a command that we can handle.
+    if (!DownloadsViewUI.isCommandName(aCommand)) {
+      return false;
+    }
+    if (!(aCommand in this) &&
+        !(aCommand in HistoryDownloadElementShell.prototype)) {
+      return false;
+    }
+    // If this function returns true, other controllers won't get a chance to
+    // process the command even if isCommandEnabled returns false, so it's
+    // important to check if the list is focused here to handle common commands
+    // like copy and paste correctly. The clear downloads command, instead, is
+    // specific to the downloads list but can be invoked from the toolbar, so we
+    // can just return true unconditionally.
+    return aCommand == "downloadsCmd_clearDownloads" ||
+           document.activeElement == this._richlistbox;
+  },
+
+  // nsIController
+  isCommandEnabled(aCommand) {
+    switch (aCommand) {
+      case "cmd_copy":
+        return this._richlistbox.selectedItems.length > 0;
+      case "cmd_selectAll":
+        return true;
+      case "cmd_paste":
+        return this._canDownloadClipboardURL();
+      case "downloadsCmd_clearDownloads":
+        return this._canClearDownloads();
+      default:
+        return Array.every(this._richlistbox.selectedItems,
+                           element => element._shell.isCommandEnabled(aCommand));
+    }
+  },
+
+  _canClearDownloads() {
+    // Downloads can be cleared if there's at least one removable download in
+    // the list (either a history download or a completed session download).
+    // Because history downloads are always removable and are listed after the
+    // session downloads, check from bottom to top.
+    for (let elt = this._richlistbox.lastChild; elt; elt = elt.previousSibling) {
+      // Stopped, paused, and failed downloads with partial data are removed.
+      let download = elt._shell.download;
+      if (download.stopped && !(download.canceled && download.hasPartialData)) {
+        return true;
+      }
+    }
+    return false;
+  },
+
+  _copySelectedDownloadsToClipboard() {
+    let urls = [for (element of this._richlistbox.selectedItems)
+                element._shell.download.source.url];
+
+    Cc["@mozilla.org/widget/clipboardhelper;1"]
+      .getService(Ci.nsIClipboardHelper)
+      .copyString(urls.join("\n"));
+  },
+
+  _getURLFromClipboardData() {
+    let trans = Cc["@mozilla.org/widget/transferable;1"].
+                createInstance(Ci.nsITransferable);
+    trans.init(null);
+
+    let flavors = ["text/x-moz-url", "text/unicode"];
+    flavors.forEach(trans.addDataFlavor);
+
+    Services.clipboard.getData(trans, Services.clipboard.kGlobalClipboard);
+
+    // Getting the data or creating the nsIURI might fail.
+    try {
+      let data = {};
+      trans.getAnyTransferData({}, data, {});
+      let [url, name] = data.value.QueryInterface(Ci.nsISupportsString)
+                            .data.split("\n");
+      if (url) {
+        return [NetUtil.newURI(url, null, null).spec, name];
+      }
+    } catch (ex) {}
+
+    return ["", ""];
+  },
+
+  _canDownloadClipboardURL() {
+    let [url, name] = this._getURLFromClipboardData();
+    return url != "";
+  },
+
+  _downloadURLFromClipboard() {
+    let [url, name] = this._getURLFromClipboardData();
+    let browserWin = RecentWindow.getMostRecentBrowserWindow();
+    let initiatingDoc = browserWin ? browserWin.document : document;
+    DownloadURL(url, name, initiatingDoc);
+  },
+
+  // nsIController
+  doCommand(aCommand) {
+    // Commands may be invoked with keyboard shortcuts even if disabled.
+    if (!this.isCommandEnabled(aCommand)) {
+      return;
+    }
+
+    // If this command is not selection-specific, execute it.
+    if (aCommand in this) {
+      this[aCommand]();
+      return;
+    }
+
+    // Cloning the nodelist into an array to get a frozen list of selected items.
+    // Otherwise, the selectedItems nodelist is live and doCommand may alter the
+    // selection while we are trying to do one particular action, like removing
+    // items from history.
+    let selectedElements = [...this._richlistbox.selectedItems];
+    for (let element of selectedElements) {
+      element._shell.doCommand(aCommand);
+    }
+  },
+
+  // nsIController
+  onEvent() {},
+
+  cmd_copy() {
+    this._copySelectedDownloadsToClipboard();
+  },
+
+  cmd_selectAll() {
+    this._richlistbox.selectAll();
+  },
+
+  cmd_paste() {
+    this._downloadURLFromClipboard();
+  },
+
+  downloadsCmd_clearDownloads() {
+    this._downloadsData.removeFinished();
+    if (this.result) {
+      Cc["@mozilla.org/browser/download-history;1"]
+        .getService(Ci.nsIDownloadHistory)
+        .removeAllDownloads();
+    }
+    // There may be no selection or focus change as a result
+    // of these change, and we want the command updated immediately.
+    goUpdateCommand("downloadsCmd_clearDownloads");
+  },
+
+  onContextMenu(aEvent) {
+    let element = this._richlistbox.selectedItem;
+    if (!element || !element._shell) {
+      return false;
+    }
+
+    // Set the state attribute so that only the appropriate items are displayed.
+    let contextMenu = document.getElementById("downloadsContextMenu");
+    let download = element._shell.download;
+    contextMenu.setAttribute("state",
+                             DownloadsCommon.stateOfDownload(download));
+    contextMenu.classList.toggle("temporary-block",
+                                 !!download.hasBlockedData);
+
+    if (!download.stopped) {
+      // The hasPartialData property of a download may change at any time after
+      // it has started, so ensure we update the related command now.
+      goUpdateCommand("downloadsCmd_pauseResume");
+    }
+
+    return true;
+  },
+
+  onKeyPress(aEvent) {
+    let selectedElements = this._richlistbox.selectedItems;
+    if (aEvent.keyCode == KeyEvent.DOM_VK_RETURN) {
+      // In the content tree, opening bookmarks by pressing return is only
+      // supported when a single item is selected. To be consistent, do the
+      // same here.
+      if (selectedElements.length == 1) {
+        let element = selectedElements[0];
+        if (element._shell) {
+          element._shell.doDefaultCommand();
+        }
+      }
+    }
+    else if (aEvent.charCode == " ".charCodeAt(0)) {
+      // Pause/Resume every selected download
+      for (let element of selectedElements) {
+        if (element._shell.isCommandEnabled("downloadsCmd_pauseResume")) {
+          element._shell.doCommand("downloadsCmd_pauseResume");
+        }
+      }
+    }
+  },
+
+  onDoubleClick(aEvent) {
+    if (aEvent.button != 0) {
+      return;
+    }
+
+    let selectedElements = this._richlistbox.selectedItems;
+    if (selectedElements.length != 1) {
+      return;
+    }
+
+    let element = selectedElements[0];
+    if (element._shell) {
+      element._shell.doDefaultCommand();
+    }
+  },
+
+  onScroll() {
+    this._ensureVisibleElementsAreActive();
+  },
+
+  onSelect() {
+    goUpdateDownloadCommands();
+
+    let selectedElements = this._richlistbox.selectedItems;
+    for (let elt of selectedElements) {
+      if (elt._shell) {
+        elt._shell.onSelect();
+      }
+    }
+  },
+
+  onDragStart(aEvent) {
+    // TODO Bug 831358: Support d&d for multiple selection.
+    // For now, we just drag the first element.
+    let selectedItem = this._richlistbox.selectedItem;
+    if (!selectedItem) {
+      return;
+    }
+
+    let targetPath = selectedItem._shell.download.target.path;
+    if (!targetPath) {
+      return;
+    }
+
+    // We must check for existence synchronously because this is a DOM event.
+    let file = new FileUtils.File(targetPath);
+    if (!file.exists()) {
+      return;
+    }
+
+    let dt = aEvent.dataTransfer;
+    dt.mozSetDataAt("application/x-moz-file", file, 0);
+    let url = Services.io.newFileURI(file).spec;
+    dt.setData("text/uri-list", url);
+    dt.setData("text/plain", url);
+    dt.effectAllowed = "copyMove";
+    dt.addElement(selectedItem);
+  },
+
+  onDragOver(aEvent) {
+    let types = aEvent.dataTransfer.types;
+    if (types.includes("text/uri-list") ||
+        types.includes("text/x-moz-url") ||
+        types.includes("text/plain")) {
+      aEvent.preventDefault();
+    }
+  },
+
+  onDrop(aEvent) {
+    let dt = aEvent.dataTransfer;
+    // If dragged item is from our source, do not try to
+    // redownload already downloaded file.
+    if (dt.mozGetDataAt("application/x-moz-file", 0)) {
+      return;
+    }
+
+    let links = Services.droppedLinkHandler.dropLinks(aEvent);
+    if (!links.length)
+      return;
+    let browserWin = RecentWindow.getMostRecentBrowserWindow();
+    let initiatingDoc = browserWin ? browserWin.document : document;
+    for (let link of links) {
+      if (link.url.startsWith("about:"))
+        continue;
+      DownloadURL(link.url, link.name, initiatingDoc);
+    }
+  },
+};
+
+for (let methodName of ["load", "applyFilter", "selectNode", "selectItems"]) {
+  DownloadsPlacesView.prototype[methodName] = function () {
+    throw new Error("|" + methodName +
+                    "| is not implemented by the downloads view.");
+  }
+}
+
+function goUpdateDownloadCommands() {
+  function updateCommandsForObject(object) {
+    for (let name in object) {
+      if (DownloadsViewUI.isCommandName(name)) {
+        goUpdateCommand(name);
+      }
+    }
+  }
+  updateCommandsForObject(DownloadsPlacesView.prototype);
+  updateCommandsForObject(HistoryDownloadElementShell.prototype);
+}
diff --git a/browser/components/downloads/content/allDownloadsViewOverlay.xul b/browser/components/downloads/content/allDownloadsViewOverlay.xul
new file mode 100644
index 000000000..cb8c699bf
--- /dev/null
+++ b/browser/components/downloads/content/allDownloadsViewOverlay.xul
@@ -0,0 +1,131 @@
+<?xml version="1.0"?>
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+<?xml-stylesheet href="chrome://browser/content/downloads/downloads.css"?>
+<?xml-stylesheet href="chrome://browser/skin/downloads/allDownloadsViewOverlay.css"?>
+
+<!DOCTYPE overlay [
+<!ENTITY % downloadsDTD SYSTEM "chrome://browser/locale/downloads/downloads.dtd">
+%downloadsDTD;
+]>
+
+<!-- This overlay provides a downloads view that lists both session downloads,
+     using the DownloadsView API, and history downloads, using places queries.
+     The view also implements a command controller and a context menu for
+     managing the downloads list.  In order to use this view:
+     1. Apply this overlay to your window.
+     2. Insert in all the overlay entry-points, namely:
+        <richlistbox id="downloadsRichListBox"/>
+        <commandset id="downloadCommands"/>
+        <menupopup id="downloadsContextMenu"/>
+    3. Make sure your window has the editMenuOverlay overlay applied,
+       because the view implements cmd_copy and cmd_delete.
+    4. Make sure your window has the globalOverlay.js script loaded.
+    5. To initialize the view
+        let view = new DownloadsPlacesView(document.getElementById("downloadsRichListBox"));
+        // This is what the Places Library uses. It could be tweaked a bit as long as the
+        // transition-type is set correctly
+        view.place = "place:transition=7&sort=4";
+-->
+<overlay id="downloadsViewOverlay"
+         xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+
+  <script type="application/javascript"
+          src="chrome://browser/content/downloads/allDownloadsViewOverlay.js"/>
+  <script type="application/javascript"
+          src="chrome://global/content/contentAreaUtils.js"/>
+
+  <richlistbox flex="1"
+               seltype="multiple"
+               id="downloadsRichListBox" context="downloadsContextMenu"
+               onscroll="return this._placesView.onScroll();"
+               onkeypress="return this._placesView.onKeyPress(event);"
+               ondblclick="return this._placesView.onDoubleClick(event);"
+               oncontextmenu="return this._placesView.onContextMenu(event);"
+               ondragstart="this._placesView.onDragStart(event);"
+               ondragover="this._placesView.onDragOver(event);"
+               ondrop="this._placesView.onDrop(event);"
+               onfocus="goUpdateDownloadCommands();"
+               onselect="this._placesView.onSelect();"
+               onblur="goUpdateDownloadCommands();"/>
+
+  <commandset id="downloadCommands"
+              commandupdater="true"
+              events="focus,select,contextmenu"
+              oncommandupdate="goUpdateDownloadCommands();">
+    <command id="downloadsCmd_pauseResume"
+             oncommand="goDoCommand('downloadsCmd_pauseResume')"/>
+    <command id="downloadsCmd_cancel"
+             oncommand="goDoCommand('downloadsCmd_cancel')"/>
+    <command id="downloadsCmd_unblock"
+             oncommand="goDoCommand('downloadsCmd_unblock')"/>
+    <command id="downloadsCmd_chooseUnblock"
+             oncommand="goDoCommand('downloadsCmd_chooseUnblock')"/>
+    <command id="downloadsCmd_chooseOpen"
+             oncommand="goDoCommand('downloadsCmd_chooseOpen')"/>
+    <command id="downloadsCmd_confirmBlock"
+             oncommand="goDoCommand('downloadsCmd_confirmBlock')"/>
+    <command id="downloadsCmd_open"
+             oncommand="goDoCommand('downloadsCmd_open')"/>
+    <command id="downloadsCmd_show"
+             oncommand="goDoCommand('downloadsCmd_show')"/>
+    <command id="downloadsCmd_retry"
+             oncommand="goDoCommand('downloadsCmd_retry')"/>
+    <command id="downloadsCmd_openReferrer"
+             oncommand="goDoCommand('downloadsCmd_openReferrer')"/>
+    <command id="downloadsCmd_clearDownloads"
+             oncommand="goDoCommand('downloadsCmd_clearDownloads')"/>
+  </commandset>
+
+  <menupopup id="downloadsContextMenu" class="download-state">
+    <menuitem command="downloadsCmd_pauseResume"
+              class="downloadPauseMenuItem"
+              label="&cmd.pause.label;"
+              accesskey="&cmd.pause.accesskey;"/>
+    <menuitem command="downloadsCmd_pauseResume"
+              class="downloadResumeMenuItem"
+              label="&cmd.resume.label;"
+              accesskey="&cmd.resume.accesskey;"/>
+    <menuitem command="downloadsCmd_cancel"
+              class="downloadCancelMenuItem"
+              label="&cmd.cancel.label;"
+              accesskey="&cmd.cancel.accesskey;"/>
+    <menuitem command="downloadsCmd_unblock"
+              class="downloadUnblockMenuItem"
+              label="&cmd.unblock2.label;"
+              accesskey="&cmd.unblock2.accesskey;"/>
+    <menuitem command="cmd_delete"
+              class="downloadRemoveFromHistoryMenuItem"
+              label="&cmd.removeFromHistory.label;"
+              accesskey="&cmd.removeFromHistory.accesskey;"/>
+    <menuitem command="downloadsCmd_show"
+              class="downloadShowMenuItem"
+#ifdef XP_MACOSX
+              label="&cmd.showMac.label;"
+              accesskey="&cmd.showMac.accesskey;"
+#else
+              label="&cmd.show.label;"
+              accesskey="&cmd.show.accesskey;"
+#endif
+              />
+
+    <menuseparator class="downloadCommandsSeparator"/>
+
+    <menuitem command="downloadsCmd_openReferrer"
+              label="&cmd.goToDownloadPage.label;"
+              accesskey="&cmd.goToDownloadPage.accesskey;"/>
+    <menuitem command="cmd_copy"
+              label="&cmd.copyDownloadLink.label;"
+              accesskey="&cmd.copyDownloadLink.accesskey;"/>
+
+    <menuseparator/>
+
+    <menuitem command="downloadsCmd_clearDownloads"
+              label="&cmd.clearDownloads.label;"
+              accesskey="&cmd.clearDownloads.accesskey;"/>
+  </menupopup>
+</overlay>
diff --git a/browser/components/downloads/content/contentAreaDownloadsView.css b/browser/components/downloads/content/contentAreaDownloadsView.css
new file mode 100644
index 000000000..abaae1f7b
--- /dev/null
+++ b/browser/components/downloads/content/contentAreaDownloadsView.css
@@ -0,0 +1,11 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#downloadsListEmptyDescription {
+  display: none;
+}
+
+#downloadsRichListBox:empty + #downloadsListEmptyDescription {
+  display: -moz-box;
+}
diff --git a/browser/components/downloads/content/contentAreaDownloadsView.js b/browser/components/downloads/content/contentAreaDownloadsView.js
new file mode 100644
index 000000000..6e4f18599
--- /dev/null
+++ b/browser/components/downloads/content/contentAreaDownloadsView.js
@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+Components.utils.import("resource://gre/modules/PrivateBrowsingUtils.jsm");
+
+var ContentAreaDownloadsView = {
+  init() {
+    let view = new DownloadsPlacesView(document.getElementById("downloadsRichListBox"));
+    // Do not display the Places downloads in private windows
+    if (!PrivateBrowsingUtils.isContentWindowPrivate(window)) {
+      view.place = "place:transition=7&sort=4";
+    }
+    // Set focus to Downloads list once it is created
+    document.getElementById("downloadsRichListBox").focus();
+  },
+};
diff --git a/browser/components/downloads/content/contentAreaDownloadsView.xul b/browser/components/downloads/content/contentAreaDownloadsView.xul
new file mode 100644
index 000000000..91c986656
--- /dev/null
+++ b/browser/components/downloads/content/contentAreaDownloadsView.xul
@@ -0,0 +1,46 @@
+<?xml version="1.0"?>
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+<?xml-stylesheet href="chrome://global/skin/"?>
+<?xml-stylesheet href="chrome://browser/content/downloads/contentAreaDownloadsView.css"?>
+<?xml-stylesheet href="chrome://browser/skin/downloads/contentAreaDownloadsView.css"?>
+
+<?xul-overlay href="chrome://browser/content/downloads/allDownloadsViewOverlay.xul"?>
+
+<?xul-overlay href="chrome://global/content/editMenuOverlay.xul"?>
+
+<!DOCTYPE window [
+<!ENTITY % downloadsDTD SYSTEM "chrome://browser/locale/downloads/downloads.dtd">
+%downloadsDTD;
+]>
+
+<window id="contentAreaDownloadsView"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        title="&downloads.title;"
+        onload="ContentAreaDownloadsView.init();">
+
+  <script type="application/javascript"
+          src="chrome://global/content/globalOverlay.js"/>
+  <script type="application/javascript"
+          src="chrome://browser/content/downloads/contentAreaDownloadsView.js"/>
+
+  <commandset id="editMenuCommands"/>
+
+  <keyset id="editMenuKeys">
+#ifdef XP_MACOSX
+    <key id="key_delete2" keycode="VK_BACK" command="cmd_delete"/>
+#endif
+  </keyset>
+
+  <stack flex="1">
+    <richlistbox id="downloadsRichListBox"/>
+    <description id="downloadsListEmptyDescription"
+                 value="&downloadsListEmpty.label;"
+                 mousethrough="always"/>
+  </stack>
+  <commandset id="downloadCommands"/>
+  <menupopup id="downloadsContextMenu"/>
+</window>
diff --git a/browser/components/downloads/content/download.xml b/browser/components/downloads/content/download.xml
new file mode 100644
index 000000000..29a1530fd
--- /dev/null
+++ b/browser/components/downloads/content/download.xml
@@ -0,0 +1,99 @@
+<?xml version="1.0"?>
+<!-- -*- Mode: HTML; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- -->
+<!-- vim: set ts=2 et sw=2 tw=80: -->
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this file,
+   - You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!DOCTYPE bindings SYSTEM "chrome://browser/locale/downloads/downloads.dtd">
+
+<bindings id="downloadBindings"
+          xmlns="http://www.mozilla.org/xbl"
+          xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+          xmlns:xbl="http://www.mozilla.org/xbl">
+
+  <binding id="download"
+           extends="chrome://global/content/bindings/richlistbox.xml#richlistitem">
+    <content orient="horizontal"
+             onclick="DownloadsView.onDownloadClick(event);">
+      <xul:hbox class="downloadMainArea"
+                flex="1"
+                align="center">
+        <xul:stack>
+          <xul:image class="downloadTypeIcon"
+                     validate="always"
+                     xbl:inherits="src=image"/>
+          <xul:image class="downloadBlockedBadge" />
+        </xul:stack>
+        <xul:vbox pack="center"
+                  flex="1"
+                  class="downloadContainer"
+                  style="width: &downloadDetails.width;">
+          <!-- We're letting localizers put a min-width in here primarily
+               because of the downloads summary at the bottom of the list of
+               download items. An element in the summary has the same min-width
+               on a description, and we don't want the panel to change size if the
+               summary isn't being displayed, so we ensure that items share the
+               same minimum width.
+               -->
+          <xul:description class="downloadTarget"
+                           crop="center"
+                           style="min-width: &downloadsSummary.minWidth2;"
+                           xbl:inherits="value=displayName,tooltiptext=displayName"/>
+          <xul:progressmeter anonid="progressmeter"
+                             class="downloadProgress"
+                             min="0"
+                             max="100"
+                             xbl:inherits="mode=progressmode,value=progress,paused=progresspaused"/>
+          <xul:description class="downloadDetails"
+                           crop="end"
+                           xbl:inherits="value=status,tooltiptext=statusTip"/>
+        </xul:vbox>
+      </xul:hbox>
+      <xul:toolbarseparator />
+      <xul:stack class="downloadButtonArea">
+        <xul:button class="downloadButton downloadCancel downloadIconCancel"
+                    tooltiptext="&cmd.cancel.label;"
+                    oncommand="DownloadsView.onDownloadCommand(event, 'downloadsCmd_cancel');"/>
+        <xul:button class="downloadButton downloadRetry downloadIconRetry"
+                    tooltiptext="&cmd.retry.label;"
+                    oncommand="DownloadsView.onDownloadCommand(event, 'downloadsCmd_retry');"/>
+        <xul:button class="downloadButton downloadShow downloadIconShow"
+#ifdef XP_MACOSX
+                    tooltiptext="&cmd.showMac.label;"
+#else
+                    tooltiptext="&cmd.show.label;"
+#endif
+                    oncommand="DownloadsView.onDownloadCommand(event, 'downloadsCmd_show');"/>
+        <xul:button class="downloadButton downloadConfirmBlock downloadIconCancel"
+                    tooltiptext="&cmd.removeFile.label;"
+                    oncommand="DownloadsView.onDownloadCommand(event, 'downloadsCmd_confirmBlock');"/>
+        <xul:button class="downloadButton downloadChooseUnblock downloadIconShow"
+                    tooltiptext="&cmd.chooseUnblock.label;"
+                    oncommand="DownloadsView.onDownloadCommand(event, 'downloadsCmd_chooseUnblock');"/>
+        <xul:button class="downloadButton downloadChooseOpen downloadIconShow"
+                    tooltiptext="&cmd.chooseOpen.label;"
+                    oncommand="DownloadsView.onDownloadCommand(event, 'downloadsCmd_chooseOpen');"/>
+        <xul:button class="downloadButton downloadShowBlockedInfo"
+                    tooltiptext="&cmd.chooseUnblock.label;"
+                    oncommand="DownloadsView.onDownloadCommand(event, 'downloadsCmd_showBlockedInfo');"/>
+      </xul:stack>
+    </content>
+  </binding>
+
+  <binding id="download-toolbarbutton"
+           extends="chrome://global/content/bindings/toolbarbutton.xml#toolbarbutton-badged">
+    <content>
+      <xul:stack class="toolbarbutton-badge-stack">
+        <children />
+        <xul:image class="toolbarbutton-icon" xbl:inherits="validate,src=image,label,consumeanchor"/>
+        <xul:label class="toolbarbutton-badge" xbl:inherits="value=badge" top="0" end="0" crop="none"/>
+      </xul:stack>
+      <xul:label class="toolbarbutton-text" crop="right" flex="1"
+                 xbl:inherits="value=label,accesskey,crop,wrap"/>
+      <xul:label class="toolbarbutton-multiline-text" flex="1"
+                 xbl:inherits="xbl:text=label,accesskey,wrap"/>
+    </content>
+  </binding>
+</bindings>
diff --git a/browser/components/downloads/content/downloads.css b/browser/components/downloads/content/downloads.css
new file mode 100644
index 000000000..dd47c6f91
--- /dev/null
+++ b/browser/components/downloads/content/downloads.css
@@ -0,0 +1,267 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*** Downloads Panel ***/
+
+richlistitem[type="download"] {
+  -moz-binding: url('chrome://browser/content/downloads/download.xml#download');
+}
+
+richlistitem[type="download"]:not([selected]) button {
+  /* Only focus buttons in the selected item. */
+  -moz-user-focus: none;
+}
+
+.downloadsHideDropmarker > #downloadsFooterButtonsSplitter,
+.downloadsHideDropmarker > #downloadsFooterDropmarker {
+  display: none;
+}
+
+richlistitem[type="download"].download-state[state="1"]:not([exists]) > .downloadButtonArea,
+richlistitem[type="download"].download-state[state="1"]:not([exists]) > toolbarseparator {
+  display: none;
+}
+
+#downloadsSummary:not([inprogress]) > vbox > #downloadsSummaryProgress,
+#downloadsSummary:not([inprogress]) > vbox > #downloadsSummaryDetails,
+#downloadsFooter:not([showingsummary]) #downloadsSummary {
+  display: none;
+}
+
+#downloadsFooter[showingdropdown] > stack > #downloadsSummary,
+#downloadsFooter[showingsummary] > stack:hover > #downloadsSummary,
+#downloadsFooter[showingsummary]:not([showingdropdown]) > stack:not(:hover) > #downloadsFooterButtons {
+  /* If we used "visibility: hidden;" then the mouseenter event of
+     #downloadsHistory wouldn't be triggered immediately, and the hover styling
+     of the button would not apply until the mouse is moved again.
+
+     "-moz-user-focus: ignore;" prevents the elements with "opacity: 0;" from
+     being focused with the keyboard. */
+  opacity: 0;
+  -moz-user-focus: ignore;
+}
+
+/*** Downloads View ***/
+
+/**
+ * The downloads richlistbox may list thousands of items, and it turns out
+ * XBL binding attachment, and even more so detachment, is a performance hog.
+ * This hack makes sure we don't apply any binding to inactive items (inactive
+ * items are history downloads that haven't been in the visible area).
+ * We can do this because the richlistbox implementation does not interact
+ * much with the richlistitem binding.  However, this may turn out to have
+ * some side effects (see bug 828111 for the details).
+ *
+ * We might be able to do away with this workaround once bug 653881 is fixed.
+ */
+richlistitem.download {
+  -moz-binding: none;
+}
+
+richlistitem.download[active] {
+  -moz-binding: url("chrome://browser/content/downloads/download.xml#download");
+}
+
+richlistitem.download button {
+  /* These buttons should never get focus, as that would "disable"
+     the downloads view controller (it's only used when the richlistbox
+     is focused). */
+  -moz-user-focus: none;
+}
+
+/*** Visibility of controls inside download items ***/
+.download-state:not(:-moz-any([state="6"], /* Blocked (parental) */
+                              [state="8"], /* Blocked (dirty)    */
+                              [state="9"]) /* Blocked (policy)   */)
+                                           .downloadBlockedBadge,
+
+.download-state:not(:-moz-any([state="-1"],/* Starting (initial) */
+                              [state="5"], /* Starting (queued)  */
+                              [state="0"], /* Downloading        */
+                              [state="4"], /* Paused             */
+                              [state="7"]) /* Scanning           */)
+                                           .downloadProgress,
+
+.download-state:not(          [state="0"]  /* Downloading        */)
+                                           .downloadPauseMenuItem,
+
+.download-state:not(          [state="4"]  /* Paused             */)
+                                           .downloadResumeMenuItem,
+
+/* Blocked (dirty) downloads that have not been confirmed and
+   have temporary data. */
+.download-state:not(          [state="8"]  /* Blocked (dirty)    */)
+                                           .downloadUnblockMenuItem,
+.download-state[state="8"]:not(.temporary-block)
+                                           .downloadUnblockMenuItem,
+
+.download-state:not(:-moz-any([state="2"], /* Failed             */
+                              [state="4"]) /* Paused             */)
+                                           .downloadCancelMenuItem,
+
+.download-state:not(:-moz-any([state="1"], /* Finished           */
+                              [state="2"], /* Failed             */
+                              [state="3"], /* Canceled           */
+                              [state="6"], /* Blocked (parental) */
+                              [state="8"], /* Blocked (dirty)    */
+                              [state="9"]) /* Blocked (policy)   */)
+                                           .downloadRemoveFromHistoryMenuItem,
+
+.download-state:not(:-moz-any([state="-1"],/* Starting (initial) */
+                              [state="0"], /* Downloading        */
+                              [state="1"], /* Finished           */
+                              [state="4"], /* Paused             */
+                              [state="5"]) /* Starting (queued)  */)
+                                           .downloadShowMenuItem,
+
+.download-state[state="7"]                 .downloadCommandsSeparator
+
+{
+  display: none;
+}
+
+/*** Visibility of download buttons ***/
+
+.download-state:not(:-moz-any([state="-1"],/* Starting (initial) */
+                              [state="5"], /* Starting (queued)  */
+                              [state="0"], /* Downloading        */
+                              [state="4"]) /* Paused             */)
+                                           .downloadCancel,
+
+/* Blocked (dirty) downloads that have not been confirmed and
+   have temporary data, for the Malware case. */
+.download-state:not(          [state="8"]  /* Blocked (dirty)    */)
+                                           .downloadConfirmBlock,
+.download-state[state="8"]:not(.temporary-block)
+                                           .downloadConfirmBlock,
+.download-state[state="8"].temporary-block:not([verdict="Malware"])
+                                           .downloadConfirmBlock,
+
+/* Blocked (dirty) downloads that have not been confirmed and
+   have temporary data, for the Potentially Unwanted case. */
+.download-state:not(          [state="8"]  /* Blocked (dirty)    */)
+                                           .downloadChooseUnblock,
+.download-state[state="8"]:not(.temporary-block)
+                                           .downloadChooseUnblock,
+.download-state[state="8"].temporary-block:not([verdict="PotentiallyUnwanted"])
+                                           .downloadChooseUnblock,
+
+/* Blocked (dirty) downloads that have not been confirmed and
+   have temporary data, for the Uncommon case. */
+.download-state:not(          [state="8"]  /* Blocked (dirty)    */)
+                                           .downloadChooseOpen,
+.download-state[state="8"]:not(.temporary-block)
+                                           .downloadChooseOpen,
+.download-state[state="8"].temporary-block:not([verdict="Uncommon"])
+                                           .downloadChooseOpen,
+
+.download-state:not(:-moz-any([state="2"], /* Failed             */
+                              [state="3"]) /* Canceled           */)
+                                           .downloadRetry,
+
+.download-state:not(          [state="1"]  /* Finished           */)
+                                           .downloadShow,
+
+.download-state:-moz-any(     [state="6"], /* Blocked (parental) */
+                              [state="7"], /* Scanning           */
+                              [state="9"]) /* Blocked (policy)   */
+                                           > toolbarseparator,
+
+/* The "show blocked info" button is shown only in the downloads panel. */
+.downloadShowBlockedInfo
+{
+  display: none;
+}
+
+/*** Downloads panel ***/
+
+#downloadsPanel[hasdownloads] #emptyDownloads,
+#downloadsPanel:not([hasdownloads]) #downloadsListBox {
+  display: none;
+}
+
+/*** Downloads panel multiview (main view and blocked-downloads subview) ***/
+
+/* Hide all the usual buttons. */
+#downloadsPanel-mainView .download-state[state="8"] .downloadCancel,
+#downloadsPanel-mainView .download-state[state="8"] .downloadConfirmBlock,
+#downloadsPanel-mainView .download-state[state="8"] .downloadChooseUnblock,
+#downloadsPanel-mainView .download-state[state="8"] .downloadChooseOpen,
+#downloadsPanel-mainView .download-state[state="8"] .downloadRetry,
+#downloadsPanel-mainView .download-state[state="8"] .downloadShow {
+  display: none;
+}
+
+/* Make the panel wide enough to show the download list items without improperly
+   truncating them. */
+#downloadsPanel-multiView > .panel-viewcontainer,
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack,
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack > .panel-mainview {
+  max-width: unset;
+}
+
+/* Show the "show blocked info" button. */
+#downloadsPanel-mainView .download-state[state="8"] .downloadShowBlockedInfo {
+  display: inline;
+}
+
+/** When the main view is showing... **/
+
+/* The subview should be off to the right and not visible at all. */
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype=main] > .panel-subviews {
+  transform: translateX(101%);
+  transition: transform var(--panelui-subview-transition-duration);
+}
+
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype=main] > .panel-subviews:-moz-locale-dir(rtl) {
+  transform: translateX(-101%);
+}
+
+/** When the subview is showing... **/
+
+/* Hide the buttons of all downloads except the one that triggered the
+   subview. */
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype="subview"] .download-state:not([showingsubview]) .downloadButton {
+  visibility: hidden;
+}
+
+/* For the download that triggered the subview, move its button farther to the
+   right by removing padding so that a minimum amount of the main view's right
+   edge needs to be shown. */
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype="subview"] .download-state[showingsubview] {
+  padding: 0;
+}
+
+/* The main view should slide to the left and its right edge should remain
+   visible. */
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype=subview] > .panel-mainview {
+  transform: translateX(calc(-100% + 38px));
+  transition: transform var(--panelui-subview-transition-duration);
+}
+
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype=subview] > .panel-mainview:-moz-locale-dir(rtl) {
+  transform: translateX(calc(100% - 38px));
+}
+
+/* The subview should leave the right edge of the main view uncovered. */
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack > .panel-subviews {
+  /* Use a margin instead of a transform like above so that the subview's width
+     isn't wider than the panel. */
+  -moz-margin-start: 38px !important;
+}
+
+/* Prevent keyboard interaction in the main view by preventing all elements in
+   the main view from being focused... */
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype="subview"] > .panel-mainview #downloadsListBox,
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype="subview"] > .panel-mainview richlistitem,
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype="subview"] > .panel-mainview .downloadButton,
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype="subview"] > .panel-mainview .downloadsPanelFooterButton,
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype="subview"] > .panel-mainview #downloadsSummary {
+  -moz-user-focus: ignore;
+}
+/* ... except for the downloadShowBlockedInfo button in the blocked download.
+   Selecting it with the keyboard should show the main view again. */
+#downloadsPanel-multiView > .panel-viewcontainer > .panel-viewstack[viewtype="subview"] .download-state[showingsubview] .downloadShowBlockedInfo {
+  -moz-user-focus: normal;
+}
diff --git a/browser/components/downloads/content/downloads.js b/browser/components/downloads/content/downloads.js
new file mode 100644
index 000000000..57397c815
--- /dev/null
+++ b/browser/components/downloads/content/downloads.js
@@ -0,0 +1,1732 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Handles the Downloads panel user interface for each browser window.
+ *
+ * This file includes the following constructors and global objects:
+ *
+ * DownloadsPanel
+ * Main entry point for the downloads panel interface.
+ *
+ * DownloadsOverlayLoader
+ * Allows loading the downloads panel and the status indicator interfaces on
+ * demand, to improve startup performance.
+ *
+ * DownloadsView
+ * Builds and updates the downloads list widget, responding to changes in the
+ * download state and real-time data.  In addition, handles part of the user
+ * interaction events raised by the downloads list widget.
+ *
+ * DownloadsViewItem
+ * Builds and updates a single item in the downloads list widget, responding to
+ * changes in the download state and real-time data, and handles the user
+ * interaction events related to a single item in the downloads list widgets.
+ *
+ * DownloadsViewController
+ * Handles part of the user interaction events raised by the downloads list
+ * widget, in particular the "commands" that apply to multiple items, and
+ * dispatches the commands that apply to individual items.
+ */
+
+/**
+ * A few words on focus and focusrings
+ *
+ * We do quite a few hacks in the Downloads Panel for focusrings. In fact, we
+ * basically suppress most if not all XUL-level focusrings, and style/draw
+ * them ourselves (using :focus instead of -moz-focusring). There are a few
+ * reasons for this:
+ *
+ * 1) Richlists on OSX don't have focusrings; instead, they are shown as
+ *    selected. This makes for some ambiguity when we have a focused/selected
+ *    item in the list, and the mouse is hovering a completed download (which
+ *    highlights).
+ * 2) Windows doesn't show focusrings until after the first time that tab is
+ *    pressed (and by then you're focusing the second item in the panel).
+ * 3) Richlistbox sets -moz-focusring even when we select it with a mouse.
+ *
+ * In general, the desired behaviour is to focus the first item after pressing
+ * tab/down, and show that focus with a ring. Then, if the mouse moves over
+ * the panel, to hide that focus ring; essentially resetting us to the state
+ * before pressing the key.
+ *
+ * We end up capturing the tab/down key events, and preventing their default
+ * behaviour. We then set a "keyfocus" attribute on the panel, which allows
+ * us to draw a ring around the currently focused element. If the panel is
+ * closed or the mouse moves over the panel, we remove the attribute.
+ */
+
+"use strict";
+
+var { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "DownloadsCommon",
+                                  "resource:///modules/DownloadsCommon.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "DownloadsViewUI",
+                                  "resource:///modules/DownloadsViewUI.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "FileUtils",
+                                  "resource://gre/modules/FileUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
+                                  "resource://gre/modules/NetUtil.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
+                                  "resource://gre/modules/PlacesUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Services",
+                                  "resource://gre/modules/Services.jsm");
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsPanel
+
+/**
+ * Main entry point for the downloads panel interface.
+ */
+const DownloadsPanel = {
+  //////////////////////////////////////////////////////////////////////////////
+  //// Initialization and termination
+
+  /**
+   * Internal state of the downloads panel, based on one of the kState
+   * constants.  This is not the same state as the XUL panel element.
+   */
+  _state: 0,
+
+  /** The panel is not linked to downloads data yet. */
+  get kStateUninitialized() {
+    return 0;
+  },
+  /** This object is linked to data, but the panel is invisible. */
+  get kStateHidden() {
+    return 1;
+  },
+  /** The panel will be shown as soon as possible. */
+  get kStateWaitingData() {
+    return 2;
+  },
+  /** The panel is almost shown - we're just waiting to get a handle on the
+      anchor. */
+  get kStateWaitingAnchor() {
+    return 3;
+  },
+  /** The panel is open. */
+  get kStateShown() {
+    return 4;
+  },
+
+  /**
+   * Location of the panel overlay.
+   */
+  get kDownloadsOverlay() {
+    return "chrome://browser/content/downloads/downloadsOverlay.xul";
+  },
+
+  /**
+   * Starts loading the download data in background, without opening the panel.
+   * Use showPanel instead to load the data and open the panel at the same time.
+   *
+   * @param aCallback
+   *        Called when initialization is complete.
+   */
+  initialize(aCallback) {
+    DownloadsCommon.log("Attempting to initialize DownloadsPanel for a window.");
+    if (this._state != this.kStateUninitialized) {
+      DownloadsCommon.log("DownloadsPanel is already initialized.");
+      DownloadsOverlayLoader.ensureOverlayLoaded(this.kDownloadsOverlay,
+                                                 aCallback);
+      return;
+    }
+    this._state = this.kStateHidden;
+
+    window.addEventListener("unload", this.onWindowUnload, false);
+
+    // Load and resume active downloads if required.  If there are downloads to
+    // be shown in the panel, they will be loaded asynchronously.
+    DownloadsCommon.initializeAllDataLinks();
+
+    // Now that data loading has eventually started, load the required XUL
+    // elements and initialize our views.
+    DownloadsCommon.log("Ensuring DownloadsPanel overlay loaded.");
+    DownloadsOverlayLoader.ensureOverlayLoaded(this.kDownloadsOverlay, () => {
+      DownloadsViewController.initialize();
+      DownloadsCommon.log("Attaching DownloadsView...");
+      DownloadsCommon.getData(window).addView(DownloadsView);
+      DownloadsCommon.getSummary(window, DownloadsView.kItemCountLimit)
+                     .addView(DownloadsSummary);
+      DownloadsCommon.log("DownloadsView attached - the panel for this window",
+                          "should now see download items come in.");
+      DownloadsPanel._attachEventListeners();
+      DownloadsCommon.log("DownloadsPanel initialized.");
+      aCallback();
+    });
+  },
+
+  /**
+   * Closes the downloads panel and frees the internal resources related to the
+   * downloads.  The downloads panel can be reopened later, even after this
+   * function has been called.
+   */
+  terminate() {
+    DownloadsCommon.log("Attempting to terminate DownloadsPanel for a window.");
+    if (this._state == this.kStateUninitialized) {
+      DownloadsCommon.log("DownloadsPanel was never initialized. Nothing to do.");
+      return;
+    }
+
+    window.removeEventListener("unload", this.onWindowUnload, false);
+
+    // Ensure that the panel is closed before shutting down.
+    this.hidePanel();
+
+    DownloadsViewController.terminate();
+    DownloadsCommon.getData(window).removeView(DownloadsView);
+    DownloadsCommon.getSummary(window, DownloadsView.kItemCountLimit)
+                   .removeView(DownloadsSummary);
+    this._unattachEventListeners();
+
+    this._state = this.kStateUninitialized;
+
+    DownloadsSummary.active = false;
+    DownloadsCommon.log("DownloadsPanel terminated.");
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Panel interface
+
+  /**
+   * Main panel element in the browser window, or null if the panel overlay
+   * hasn't been loaded yet.
+   */
+  get panel() {
+    // If the downloads panel overlay hasn't loaded yet, just return null
+    // without resetting this.panel.
+    let downloadsPanel = document.getElementById("downloadsPanel");
+    if (!downloadsPanel)
+      return null;
+
+    delete this.panel;
+    return this.panel = downloadsPanel;
+  },
+
+  /**
+   * Starts opening the downloads panel interface, anchored to the downloads
+   * button of the browser window.  The list of downloads to display is
+   * initialized the first time this method is called, and the panel is shown
+   * only when data is ready.
+   */
+  showPanel() {
+    DownloadsCommon.log("Opening the downloads panel.");
+
+    if (this.isPanelShowing) {
+      DownloadsCommon.log("Panel is already showing - focusing instead.");
+      this._focusPanel();
+      return;
+    }
+
+    this.initialize(() => {
+      let downloadsFooterButtons =
+        document.getElementById("downloadsFooterButtons");
+      if (DownloadsCommon.showPanelDropmarker) {
+        downloadsFooterButtons.classList.remove("downloadsHideDropmarker");
+      } else {
+        downloadsFooterButtons.classList.add("downloadsHideDropmarker");
+      }
+
+      // Delay displaying the panel because this function will sometimes be
+      // called while another window is closing (like the window for selecting
+      // whether to save or open the file), and that would cause the panel to
+      // close immediately.
+      setTimeout(() => this._openPopupIfDataReady(), 0);
+    });
+
+    DownloadsCommon.log("Waiting for the downloads panel to appear.");
+    this._state = this.kStateWaitingData;
+  },
+
+  /**
+   * Hides the downloads panel, if visible, but keeps the internal state so that
+   * the panel can be reopened quickly if required.
+   */
+  hidePanel() {
+    DownloadsCommon.log("Closing the downloads panel.");
+
+    if (!this.isPanelShowing) {
+      DownloadsCommon.log("Downloads panel is not showing - nothing to do.");
+      return;
+    }
+
+    this.panel.hidePopup();
+
+    // Ensure that we allow the panel to be reopened.  Note that, if the popup
+    // was open, then the onPopupHidden event handler has already updated the
+    // current state, otherwise we must update the state ourselves.
+    this._state = this.kStateHidden;
+    DownloadsCommon.log("Downloads panel is now closed.");
+  },
+
+  /**
+   * Indicates whether the panel is shown or will be shown.
+   */
+  get isPanelShowing() {
+    return this._state == this.kStateWaitingData ||
+           this._state == this.kStateWaitingAnchor ||
+           this._state == this.kStateShown;
+  },
+
+  /**
+   * Returns whether the user has started keyboard navigation.
+   */
+  get keyFocusing() {
+    return this.panel.hasAttribute("keyfocus");
+  },
+
+  /**
+   * Set to true if the user has started keyboard navigation, and we should be
+   * showing focusrings in the panel. Also adds a mousemove event handler to
+   * the panel which disables keyFocusing.
+   */
+  set keyFocusing(aValue) {
+    if (aValue) {
+      this.panel.setAttribute("keyfocus", "true");
+      this.panel.addEventListener("mousemove", this);
+    } else {
+      this.panel.removeAttribute("keyfocus");
+      this.panel.removeEventListener("mousemove", this);
+    }
+    return aValue;
+  },
+
+  /**
+   * Handles the mousemove event for the panel, which disables focusring
+   * visualization.
+   */
+  handleEvent(aEvent) {
+    switch (aEvent.type) {
+      case "mousemove":
+        this.keyFocusing = false;
+        break;
+      case "keydown":
+        return this._onKeyDown(aEvent);
+      case "keypress":
+        return this._onKeyPress(aEvent);
+      case "popupshown":
+        if (this.setHeightToFitOnShow) {
+          this.setHeightToFitOnShow = false;
+          this.setHeightToFit();
+        }
+        break;
+    }
+  },
+
+  setHeightToFit() {
+    if (this._state == this.kStateShown) {
+      DownloadsBlockedSubview.view.setHeightToFit();
+    } else {
+      this.setHeightToFitOnShow = true;
+    }
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Callback functions from DownloadsView
+
+  /**
+   * Called after data loading finished.
+   */
+  onViewLoadCompleted() {
+    this._openPopupIfDataReady();
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// User interface event functions
+
+  onWindowUnload() {
+    // This function is registered as an event listener, we can't use "this".
+    DownloadsPanel.terminate();
+  },
+
+  onPopupShown(aEvent) {
+    // Ignore events raised by nested popups.
+    if (aEvent.target != aEvent.currentTarget) {
+      return;
+    }
+
+    DownloadsCommon.log("Downloads panel has shown.");
+    this._state = this.kStateShown;
+
+    // Since at most one popup is open at any given time, we can set globally.
+    DownloadsCommon.getIndicatorData(window).attentionSuppressed = true;
+
+    // Ensure that the first item is selected when the panel is focused.
+    if (DownloadsView.richListBox.itemCount > 0 &&
+        DownloadsView.richListBox.selectedIndex == -1) {
+      DownloadsView.richListBox.selectedIndex = 0;
+    }
+
+    this._focusPanel();
+  },
+
+  onPopupHidden(aEvent) {
+    // Ignore events raised by nested popups.
+    if (aEvent.target != aEvent.currentTarget) {
+      return;
+    }
+
+    DownloadsCommon.log("Downloads panel has hidden.");
+
+    // Removes the keyfocus attribute so that we stop handling keyboard
+    // navigation.
+    this.keyFocusing = false;
+
+    // Since at most one popup is open at any given time, we can set globally.
+    DownloadsCommon.getIndicatorData(window).attentionSuppressed = false;
+
+    // Allow the anchor to be hidden.
+    DownloadsButton.releaseAnchor();
+
+    // Allow the panel to be reopened.
+    this._state = this.kStateHidden;
+  },
+
+  onFooterPopupShowing(aEvent) {
+    let itemClearList = document.getElementById("downloadsDropdownItemClearList");
+    if (DownloadsCommon.getData(window).canRemoveFinished) {
+      itemClearList.removeAttribute("hidden");
+    } else {
+      itemClearList.setAttribute("hidden", "true");
+    }
+    DownloadsViewController.updateCommands();
+
+    document.getElementById("downloadsFooter")
+      .setAttribute("showingdropdown", true);
+  },
+
+  onFooterPopupHidden(aEvent) {
+    document.getElementById("downloadsFooter")
+      .removeAttribute("showingdropdown");
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Related operations
+
+  /**
+   * Shows or focuses the user interface dedicated to downloads history.
+   */
+  showDownloadsHistory() {
+    DownloadsCommon.log("Showing download history.");
+    // Hide the panel before showing another window, otherwise focus will return
+    // to the browser window when the panel closes automatically.
+    this.hidePanel();
+
+    BrowserDownloadsUI();
+  },
+
+  openDownloadsFolder() {
+    Downloads.getPreferredDownloadsDirectory().then(downloadsPath => {
+      DownloadsCommon.showDirectory(new FileUtils.File(downloadsPath));
+    }).catch(Cu.reportError);
+    this.hidePanel();
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Internal functions
+
+  /**
+   * Attach event listeners to a panel element. These listeners should be
+   * removed in _unattachEventListeners. This is called automatically after the
+   * panel has successfully loaded.
+   */
+  _attachEventListeners() {
+    // Handle keydown to support accel-V.
+    this.panel.addEventListener("keydown", this, false);
+    // Handle keypress to be able to preventDefault() events before they reach
+    // the richlistbox, for keyboard navigation.
+    this.panel.addEventListener("keypress", this, false);
+    // Handle height adjustment on show.
+    this.panel.addEventListener("popupshown", this, false);
+  },
+
+  /**
+   * Unattach event listeners that were added in _attachEventListeners. This
+   * is called automatically on panel termination.
+   */
+  _unattachEventListeners() {
+    this.panel.removeEventListener("keydown", this, false);
+    this.panel.removeEventListener("keypress", this, false);
+    this.panel.removeEventListener("popupshown", this, false);
+  },
+
+  _onKeyPress(aEvent) {
+    // Handle unmodified keys only.
+    if (aEvent.altKey || aEvent.ctrlKey || aEvent.shiftKey || aEvent.metaKey) {
+      return;
+    }
+
+    let richListBox = DownloadsView.richListBox;
+
+    // If the user has pressed the tab, up, or down cursor key, start keyboard
+    // navigation, thus enabling focusrings in the panel.  Keyboard navigation
+    // is automatically disabled if the user moves the mouse on the panel, or
+    // if the panel is closed.
+    if ((aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_TAB ||
+        aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_UP ||
+        aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_DOWN) &&
+        !this.keyFocusing) {
+      this.keyFocusing = true;
+      // Ensure there's a selection, we will show the focus ring around it and
+      // prevent the richlistbox from changing the selection.
+      if (DownloadsView.richListBox.selectedIndex == -1) {
+        DownloadsView.richListBox.selectedIndex = 0;
+      }
+      aEvent.preventDefault();
+      return;
+    }
+
+    if (aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_DOWN) {
+      // If the last element in the list is selected, or the footer is already
+      // focused, focus the footer.
+      if (richListBox.selectedItem === richListBox.lastChild ||
+          document.activeElement.parentNode.id === "downloadsFooter") {
+        DownloadsFooter.focus();
+        aEvent.preventDefault();
+        return;
+      }
+    }
+
+    // Pass keypress events to the richlistbox view when it's focused.
+    if (document.activeElement === richListBox) {
+      DownloadsView.onDownloadKeyPress(aEvent);
+    }
+  },
+
+  /**
+   * Keydown listener that listens for the keys to start key focusing, as well
+   * as the the accel-V "paste" event, which initiates a file download if the
+   * pasted item can be resolved to a URI.
+   */
+  _onKeyDown(aEvent) {
+    // If the footer is focused and the downloads list has at least 1 element
+    // in it, focus the last element in the list when going up.
+    if (aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_UP &&
+        document.activeElement.parentNode.id === "downloadsFooter" &&
+        DownloadsView.richListBox.firstChild) {
+      DownloadsView.richListBox.focus();
+      DownloadsView.richListBox.selectedItem = DownloadsView.richListBox.lastChild;
+      aEvent.preventDefault();
+      return;
+    }
+
+    let pasting = aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_V &&
+                  aEvent.getModifierState("Accel");
+
+    if (!pasting) {
+      return;
+    }
+
+    DownloadsCommon.log("Received a paste event.");
+
+    let trans = Cc["@mozilla.org/widget/transferable;1"]
+                  .createInstance(Ci.nsITransferable);
+    trans.init(null);
+    let flavors = ["text/x-moz-url", "text/unicode"];
+    flavors.forEach(trans.addDataFlavor);
+    Services.clipboard.getData(trans, Services.clipboard.kGlobalClipboard);
+    // Getting the data or creating the nsIURI might fail
+    try {
+      let data = {};
+      trans.getAnyTransferData({}, data, {});
+      let [url, name] = data.value
+                            .QueryInterface(Ci.nsISupportsString)
+                            .data
+                            .split("\n");
+      if (!url) {
+        return;
+      }
+
+      let uri = NetUtil.newURI(url);
+      DownloadsCommon.log("Pasted URL seems valid. Starting download.");
+      DownloadURL(uri.spec, name, document);
+    } catch (ex) {}
+  },
+
+  /**
+   * Move focus to the main element in the downloads panel, unless another
+   * element in the panel is already focused.
+   */
+  _focusPanel() {
+    // We may be invoked while the panel is still waiting to be shown.
+    if (this._state != this.kStateShown) {
+      return;
+    }
+
+    let element = document.commandDispatcher.focusedElement;
+    while (element && element != this.panel) {
+      element = element.parentNode;
+    }
+    if (!element) {
+      if (DownloadsView.richListBox.itemCount > 0) {
+        DownloadsView.richListBox.focus();
+      } else {
+        DownloadsFooter.focus();
+      }
+    }
+  },
+
+  /**
+   * Opens the downloads panel when data is ready to be displayed.
+   */
+  _openPopupIfDataReady() {
+    // We don't want to open the popup if we already displayed it, or if we are
+    // still loading data.
+    if (this._state != this.kStateWaitingData || DownloadsView.loading) {
+      return;
+    }
+
+    this._state = this.kStateWaitingAnchor;
+
+    // Ensure the anchor is visible.  If that is not possible, show the panel
+    // anchored to the top area of the window, near the default anchor position.
+    DownloadsButton.getAnchor(anchor => {
+      // If somehow we've switched states already (by getting a panel hiding
+      // event before an overlay is loaded, for example), bail out.
+      if (this._state != this.kStateWaitingAnchor) {
+        return;
+      }
+
+      // At this point, if the window is minimized, opening the panel could fail
+      // without any notification, and there would be no way to either open or
+      // close the panel any more.  To prevent this, check if the window is
+      // minimized and in that case force the panel to the closed state.
+      if (window.windowState == Ci.nsIDOMChromeWindow.STATE_MINIMIZED) {
+        DownloadsButton.releaseAnchor();
+        this._state = this.kStateHidden;
+        return;
+      }
+
+      if (!anchor) {
+        DownloadsCommon.error("Downloads button cannot be found.");
+        return;
+      }
+
+      // When the panel is opened, we check if the target files of visible items
+      // still exist, and update the allowed items interactions accordingly.  We
+      // do these checks on a background thread, and don't prevent the panel to
+      // be displayed while these checks are being performed.
+      for (let viewItem of DownloadsView._visibleViewItems.values()) {
+        viewItem.download.refresh().catch(Cu.reportError);
+      }
+
+      DownloadsCommon.log("Opening downloads panel popup.");
+      this.panel.openPopup(anchor, "bottomcenter topright", 0, 0, false, null);
+    });
+  },
+};
+
+XPCOMUtils.defineConstant(this, "DownloadsPanel", DownloadsPanel);
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsOverlayLoader
+
+/**
+ * Allows loading the downloads panel and the status indicator interfaces on
+ * demand, to improve startup performance.
+ */
+const DownloadsOverlayLoader = {
+  /**
+   * We cannot load two overlays at the same time, thus we use a queue of
+   * pending load requests.
+   */
+  _loadRequests: [],
+
+  /**
+   * True while we are waiting for an overlay to be loaded.
+   */
+  _overlayLoading: false,
+
+  /**
+   * This object has a key for each overlay URI that is already loaded.
+   */
+  _loadedOverlays: {},
+
+  /**
+   * Loads the specified overlay and invokes the given callback when finished.
+   *
+   * @param aOverlay
+   *        String containing the URI of the overlay to load in the current
+   *        window.  If this overlay has already been loaded using this
+   *        function, then the overlay is not loaded again.
+   * @param aCallback
+   *        Invoked when loading is completed.  If the overlay is already
+   *        loaded, the function is called immediately.
+   */
+  ensureOverlayLoaded(aOverlay, aCallback) {
+    // The overlay is already loaded, invoke the callback immediately.
+    if (aOverlay in this._loadedOverlays) {
+      aCallback();
+      return;
+    }
+
+    // The callback will be invoked when loading is finished.
+    this._loadRequests.push({ overlay: aOverlay, callback: aCallback });
+    if (this._overlayLoading) {
+      return;
+    }
+
+    this._overlayLoading = true;
+    DownloadsCommon.log("Loading overlay ", aOverlay);
+    document.loadOverlay(aOverlay, () => {
+      this._overlayLoading = false;
+      this._loadedOverlays[aOverlay] = true;
+
+      this.processPendingRequests();
+    });
+  },
+
+  /**
+   * Re-processes all the currently pending requests, invoking the callbacks
+   * and/or loading more overlays as needed.  In most cases, there will be a
+   * single request for one overlay, that will be processed immediately.
+   */
+  processPendingRequests() {
+    // Re-process all the currently pending requests, yet allow more requests
+    // to be appended at the end of the array if we're not ready for them.
+    let currentLength = this._loadRequests.length;
+    for (let i = 0; i < currentLength; i++) {
+      let request = this._loadRequests.shift();
+
+      // We must call ensureOverlayLoaded again for each request, to check if
+      // the associated callback can be invoked now, or if we must still wait
+      // for the associated overlay to load.
+      this.ensureOverlayLoaded(request.overlay, request.callback);
+    }
+  },
+};
+
+XPCOMUtils.defineConstant(this, "DownloadsOverlayLoader", DownloadsOverlayLoader);
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsView
+
+/**
+ * Builds and updates the downloads list widget, responding to changes in the
+ * download state and real-time data.  In addition, handles part of the user
+ * interaction events raised by the downloads list widget.
+ */
+const DownloadsView = {
+  //////////////////////////////////////////////////////////////////////////////
+  //// Functions handling download items in the list
+
+  /**
+   * Maximum number of items shown by the list at any given time.
+   */
+  kItemCountLimit: 5,
+
+  /**
+   * Indicates whether there is an open contextMenu for a download item.
+   */
+  contextMenuOpen: false,
+
+  /**
+   * Indicates whether there is a DownloadsBlockedSubview open.
+   */
+  subViewOpen: false,
+
+  /**
+   * Indicates whether we are still loading downloads data asynchronously.
+   */
+  loading: false,
+
+  /**
+   * Ordered array of all Download objects.  We need to keep this array because
+   * only a limited number of items are shown at once, and if an item that is
+   * currently visible is removed from the list, we might need to take another
+   * item from the array and make it appear at the bottom.
+   */
+  _downloads: [],
+
+  /**
+   * Associates the visible Download objects with their corresponding
+   * DownloadsViewItem object.  There is a limited number of view items in the
+   * panel at any given time.
+   */
+  _visibleViewItems: new Map(),
+
+  /**
+   * Called when the number of items in the list changes.
+   */
+  _itemCountChanged() {
+    DownloadsCommon.log("The downloads item count has changed - we are tracking",
+                        this._downloads.length, "downloads in total.");
+    let count = this._downloads.length;
+    let hiddenCount = count - this.kItemCountLimit;
+
+    if (count > 0) {
+      DownloadsCommon.log("Setting the panel's hasdownloads attribute to true.");
+      DownloadsPanel.panel.setAttribute("hasdownloads", "true");
+    } else {
+      DownloadsCommon.log("Removing the panel's hasdownloads attribute.");
+      DownloadsPanel.panel.removeAttribute("hasdownloads");
+    }
+
+    // If we've got some hidden downloads, we should activate the
+    // DownloadsSummary. The DownloadsSummary will determine whether or not
+    // it's appropriate to actually display the summary.
+    DownloadsSummary.active = hiddenCount > 0;
+  },
+
+  /**
+   * Element corresponding to the list of downloads.
+   */
+  get richListBox() {
+    delete this.richListBox;
+    return this.richListBox = document.getElementById("downloadsListBox");
+  },
+
+  /**
+   * Element corresponding to the button for showing more downloads.
+   */
+  get downloadsHistory() {
+    delete this.downloadsHistory;
+    return this.downloadsHistory = document.getElementById("downloadsHistory");
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Callback functions from DownloadsData
+
+  /**
+   * Called before multiple downloads are about to be loaded.
+   */
+  onDataLoadStarting() {
+    DownloadsCommon.log("onDataLoadStarting called for DownloadsView.");
+    this.loading = true;
+  },
+
+  /**
+   * Called after data loading finished.
+   */
+  onDataLoadCompleted() {
+    DownloadsCommon.log("onDataLoadCompleted called for DownloadsView.");
+
+    this.loading = false;
+
+    // We suppressed item count change notifications during the batch load, at
+    // this point we should just call the function once.
+    this._itemCountChanged();
+
+    // Notify the panel that all the initially available downloads have been
+    // loaded.  This ensures that the interface is visible, if still required.
+    DownloadsPanel.onViewLoadCompleted();
+  },
+
+  /**
+   * Called when a new download data item is available, either during the
+   * asynchronous data load or when a new download is started.
+   *
+   * @param aDownload
+   *        Download object that was just added.
+   * @param aNewest
+   *        When true, indicates that this item is the most recent and should be
+   *        added in the topmost position.  This happens when a new download is
+   *        started.  When false, indicates that the item is the least recent
+   *        and should be appended.  The latter generally happens during the
+   *        asynchronous data load.
+   */
+  onDownloadAdded(download, aNewest) {
+    DownloadsCommon.log("A new download data item was added - aNewest =",
+                        aNewest);
+
+    if (aNewest) {
+      this._downloads.unshift(download);
+    } else {
+      this._downloads.push(download);
+    }
+
+    let itemsNowOverflow = this._downloads.length > this.kItemCountLimit;
+    if (aNewest || !itemsNowOverflow) {
+      // The newly added item is visible in the panel and we must add the
+      // corresponding element.  This is either because it is the first item, or
+      // because it was added at the bottom but the list still doesn't overflow.
+      this._addViewItem(download, aNewest);
+    }
+    if (aNewest && itemsNowOverflow) {
+      // If the list overflows, remove the last item from the panel to make room
+      // for the new one that we just added at the top.
+      this._removeViewItem(this._downloads[this.kItemCountLimit]);
+    }
+
+    // For better performance during batch loads, don't update the count for
+    // every item, because the interface won't be visible until load finishes.
+    if (!this.loading) {
+      this._itemCountChanged();
+    }
+  },
+
+  onDownloadStateChanged(download) {
+    let viewItem = this._visibleViewItems.get(download);
+    if (viewItem) {
+      viewItem.onStateChanged();
+    }
+  },
+
+  onDownloadChanged(download) {
+    let viewItem = this._visibleViewItems.get(download);
+    if (viewItem) {
+      viewItem.onChanged();
+    }
+  },
+
+  /**
+   * Called when a data item is removed.  Ensures that the widget associated
+   * with the view item is removed from the user interface.
+   *
+   * @param download
+   *        Download object that is being removed.
+   */
+  onDownloadRemoved(download) {
+    DownloadsCommon.log("A download data item was removed.");
+
+    let itemIndex = this._downloads.indexOf(download);
+    this._downloads.splice(itemIndex, 1);
+
+    if (itemIndex < this.kItemCountLimit) {
+      // The item to remove is visible in the panel.
+      this._removeViewItem(download);
+      if (this._downloads.length >= this.kItemCountLimit) {
+        // Reinsert the next item into the panel.
+        this._addViewItem(this._downloads[this.kItemCountLimit - 1], false);
+      }
+    }
+
+    this._itemCountChanged();
+
+    // Adjust the panel height if we removed items.
+    DownloadsPanel.setHeightToFit();
+  },
+
+  /**
+   * Associates each richlistitem for a download with its corresponding
+   * DownloadsViewItem object.
+   */
+  _itemsForElements: new Map(),
+
+  itemForElement(element) {
+    return this._itemsForElements.get(element);
+  },
+
+  /**
+   * Creates a new view item associated with the specified data item, and adds
+   * it to the top or the bottom of the list.
+   */
+  _addViewItem(download, aNewest)
+  {
+    DownloadsCommon.log("Adding a new DownloadsViewItem to the downloads list.",
+                        "aNewest =", aNewest);
+
+    let element = document.createElement("richlistitem");
+    let viewItem = new DownloadsViewItem(download, element);
+    this._visibleViewItems.set(download, viewItem);
+    this._itemsForElements.set(element, viewItem);
+    if (aNewest) {
+      this.richListBox.insertBefore(element, this.richListBox.firstChild);
+    } else {
+      this.richListBox.appendChild(element);
+    }
+  },
+
+  /**
+   * Removes the view item associated with the specified data item.
+   */
+  _removeViewItem(download) {
+    DownloadsCommon.log("Removing a DownloadsViewItem from the downloads list.");
+    let element = this._visibleViewItems.get(download).element;
+    let previousSelectedIndex = this.richListBox.selectedIndex;
+    this.richListBox.removeChild(element);
+    if (previousSelectedIndex != -1) {
+      this.richListBox.selectedIndex = Math.min(previousSelectedIndex,
+                                                this.richListBox.itemCount - 1);
+    }
+    this._visibleViewItems.delete(download);
+    this._itemsForElements.delete(element);
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// User interface event functions
+
+  /**
+   * Helper function to do commands on a specific download item.
+   *
+   * @param aEvent
+   *        Event object for the event being handled.  If the event target is
+   *        not a richlistitem that represents a download, this function will
+   *        walk up the parent nodes until it finds a DOM node that is.
+   * @param aCommand
+   *        The command to be performed.
+   */
+  onDownloadCommand(aEvent, aCommand) {
+    let target = aEvent.target;
+    while (target.nodeName != "richlistitem") {
+      target = target.parentNode;
+    }
+    DownloadsView.itemForElement(target).doCommand(aCommand);
+  },
+
+  onDownloadClick(aEvent) {
+    // Handle primary clicks only, and exclude the action button.
+    if (aEvent.button == 0 &&
+        !aEvent.originalTarget.hasAttribute("oncommand")) {
+      let target = aEvent.target;
+      while (target.nodeName != "richlistitem") {
+        target = target.parentNode;
+      }
+      let download = DownloadsView.itemForElement(target).download;
+      if (download.hasBlockedData) {
+        goDoCommand("downloadsCmd_showBlockedInfo");
+      } else {
+        goDoCommand("downloadsCmd_open");
+      }
+    }
+  },
+
+  /**
+   * Handles keypress events on a download item.
+   */
+  onDownloadKeyPress(aEvent) {
+    // Pressing the key on buttons should not invoke the action because the
+    // event has already been handled by the button itself.
+    if (aEvent.originalTarget.hasAttribute("command") ||
+        aEvent.originalTarget.hasAttribute("oncommand")) {
+      return;
+    }
+
+    if (aEvent.charCode == " ".charCodeAt(0)) {
+      goDoCommand("downloadsCmd_pauseResume");
+      return;
+    }
+
+    if (aEvent.keyCode == KeyEvent.DOM_VK_RETURN) {
+      goDoCommand("downloadsCmd_doDefault");
+    }
+  },
+
+  /**
+   * Event handlers to keep track of context menu state (open/closed) for
+   * download items.
+   */
+  onContextPopupShown(aEvent) {
+    // Ignore events raised by nested popups.
+    if (aEvent.target != aEvent.currentTarget) {
+      return;
+    }
+
+    DownloadsCommon.log("Context menu has shown.");
+    this.contextMenuOpen = true;
+  },
+
+  onContextPopupHidden(aEvent) {
+    // Ignore events raised by nested popups.
+    if (aEvent.target != aEvent.currentTarget) {
+      return;
+    }
+
+    DownloadsCommon.log("Context menu has hidden.");
+    this.contextMenuOpen = false;
+  },
+
+  /**
+   * Mouse listeners to handle selection on hover.
+   */
+  onDownloadMouseOver(aEvent) {
+    if (!(this.contextMenuOpen || this.subViewOpen) &&
+        aEvent.target.parentNode == this.richListBox) {
+      this.richListBox.selectedItem = aEvent.target;
+    }
+  },
+
+  onDownloadMouseOut(aEvent) {
+    if (!(this.contextMenuOpen || this.subViewOpen) &&
+        aEvent.target.parentNode == this.richListBox) {
+      // If the destination element is outside of the richlistitem, clear the
+      // selection.
+      let element = aEvent.relatedTarget;
+      while (element && element != aEvent.target) {
+        element = element.parentNode;
+      }
+      if (!element) {
+        this.richListBox.selectedIndex = -1;
+      }
+    }
+  },
+
+  onDownloadContextMenu(aEvent) {
+    let element = this.richListBox.selectedItem;
+    if (!element) {
+      return;
+    }
+
+    DownloadsViewController.updateCommands();
+
+    // Set the state attribute so that only the appropriate items are displayed.
+    let contextMenu = document.getElementById("downloadsContextMenu");
+    contextMenu.setAttribute("state", element.getAttribute("state"));
+    contextMenu.classList.toggle("temporary-block",
+                                 element.classList.contains("temporary-block"));
+  },
+
+  onDownloadDragStart(aEvent) {
+    let element = this.richListBox.selectedItem;
+    if (!element) {
+      return;
+    }
+
+    // We must check for existence synchronously because this is a DOM event.
+    let file = new FileUtils.File(DownloadsView.itemForElement(element)
+                                               .download.target.path);
+    if (!file.exists()) {
+      return;
+    }
+
+    let dataTransfer = aEvent.dataTransfer;
+    dataTransfer.mozSetDataAt("application/x-moz-file", file, 0);
+    dataTransfer.effectAllowed = "copyMove";
+    let spec = NetUtil.newURI(file).spec;
+    dataTransfer.setData("text/uri-list", spec);
+    dataTransfer.setData("text/plain", spec);
+    dataTransfer.addElement(element);
+
+    aEvent.stopPropagation();
+  },
+}
+
+XPCOMUtils.defineConstant(this, "DownloadsView", DownloadsView);
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsViewItem
+
+/**
+ * Builds and updates a single item in the downloads list widget, responding to
+ * changes in the download state and real-time data, and handles the user
+ * interaction events related to a single item in the downloads list widgets.
+ *
+ * @param download
+ *        Download object to be associated with the view item.
+ * @param aElement
+ *        XUL element corresponding to the single download item in the view.
+ */
+function DownloadsViewItem(download, aElement) {
+  this.download = download;
+  this.element = aElement;
+  this.element._shell = this;
+
+  this.element.setAttribute("type", "download");
+  this.element.classList.add("download-state");
+
+  this._updateState();
+}
+
+DownloadsViewItem.prototype = {
+  __proto__: DownloadsViewUI.DownloadElementShell.prototype,
+
+  /**
+   * The XUL element corresponding to the associated richlistbox item.
+   */
+  _element: null,
+
+  onStateChanged() {
+    this._updateState();
+  },
+
+  onChanged() {
+    this._updateProgress();
+  },
+
+  isCommandEnabled(aCommand) {
+    switch (aCommand) {
+      case "downloadsCmd_open": {
+        if (!this.download.succeeded) {
+          return false;
+        }
+
+        let file = new FileUtils.File(this.download.target.path);
+        return file.exists();
+      }
+      case "downloadsCmd_show": {
+        let file = new FileUtils.File(this.download.target.path);
+        if (file.exists()) {
+          return true;
+        }
+
+        if (!this.download.target.partFilePath) {
+          return false;
+        }
+
+        let partFile = new FileUtils.File(this.download.target.partFilePath);
+        return partFile.exists();
+      }
+      case "cmd_delete":
+      case "downloadsCmd_cancel":
+      case "downloadsCmd_copyLocation":
+      case "downloadsCmd_doDefault":
+        return true;
+      case "downloadsCmd_showBlockedInfo":
+        return this.download.hasBlockedData;
+    }
+    return DownloadsViewUI.DownloadElementShell.prototype
+                          .isCommandEnabled.call(this, aCommand);
+  },
+
+  doCommand(aCommand) {
+    if (this.isCommandEnabled(aCommand)) {
+      this[aCommand]();
+    }
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Item commands
+
+  cmd_delete() {
+    DownloadsCommon.removeAndFinalizeDownload(this.download);
+    PlacesUtils.bhistory.removePage(
+                           NetUtil.newURI(this.download.source.url));
+  },
+
+  downloadsCmd_unblock() {
+    DownloadsPanel.hidePanel();
+    this.confirmUnblock(window, "unblock");
+  },
+
+  downloadsCmd_chooseUnblock() {
+    DownloadsPanel.hidePanel();
+    this.confirmUnblock(window, "chooseUnblock");
+  },
+
+  downloadsCmd_unblockAndOpen() {
+    DownloadsPanel.hidePanel();
+    this.unblockAndOpenDownload().catch(Cu.reportError);
+  },
+
+  downloadsCmd_open() {
+    this.download.launch().catch(Cu.reportError);
+
+    // We explicitly close the panel here to give the user the feedback that
+    // their click has been received, and we're handling the action.
+    // Otherwise, we'd have to wait for the file-type handler to execute
+    // before the panel would close. This also helps to prevent the user from
+    // accidentally opening a file several times.
+    DownloadsPanel.hidePanel();
+  },
+
+  downloadsCmd_show() {
+    let file = new FileUtils.File(this.download.target.path);
+    DownloadsCommon.showDownloadedFile(file);
+
+    // We explicitly close the panel here to give the user the feedback that
+    // their click has been received, and we're handling the action.
+    // Otherwise, we'd have to wait for the operating system file manager
+    // window to open before the panel closed. This also helps to prevent the
+    // user from opening the containing folder several times.
+    DownloadsPanel.hidePanel();
+  },
+
+  downloadsCmd_showBlockedInfo() {
+    DownloadsBlockedSubview.toggle(this.element,
+                                   ...this.rawBlockedTitleAndDetails);
+  },
+
+  downloadsCmd_openReferrer() {
+    openURL(this.download.source.referrer);
+  },
+
+  downloadsCmd_copyLocation() {
+    let clipboard = Cc["@mozilla.org/widget/clipboardhelper;1"]
+                    .getService(Ci.nsIClipboardHelper);
+    clipboard.copyString(this.download.source.url);
+  },
+
+  downloadsCmd_doDefault() {
+    let defaultCommand = this.currentDefaultCommandName;
+    if (defaultCommand && this.isCommandEnabled(defaultCommand)) {
+      this.doCommand(defaultCommand);
+    }
+  },
+};
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsViewController
+
+/**
+ * Handles part of the user interaction events raised by the downloads list
+ * widget, in particular the "commands" that apply to multiple items, and
+ * dispatches the commands that apply to individual items.
+ */
+const DownloadsViewController = {
+  //////////////////////////////////////////////////////////////////////////////
+  //// Initialization and termination
+
+  initialize() {
+    window.controllers.insertControllerAt(0, this);
+  },
+
+  terminate() {
+    window.controllers.removeController(this);
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// nsIController
+
+  supportsCommand(aCommand) {
+    if (aCommand === "downloadsCmd_clearList") {
+      return true;
+    }
+    // Firstly, determine if this is a command that we can handle.
+    if (!DownloadsViewUI.isCommandName(aCommand)) {
+      return false;
+    }
+    if (!(aCommand in this) &&
+        !(aCommand in DownloadsViewItem.prototype)) {
+      return false;
+    }
+    // The currently supported commands depend on whether the blocked subview is
+    // showing.  If it is, then take the following path.
+    if (DownloadsBlockedSubview.view.showingSubView) {
+      let blockedSubviewCmds = [
+        "downloadsCmd_unblockAndOpen",
+        "cmd_delete",
+      ];
+      return blockedSubviewCmds.indexOf(aCommand) >= 0;
+    }
+    // If the blocked subview is not showing, then determine if focus is on a
+    // control in the downloads list.
+    let element = document.commandDispatcher.focusedElement;
+    while (element && element != DownloadsView.richListBox) {
+      element = element.parentNode;
+    }
+    // We should handle the command only if the downloads list is among the
+    // ancestors of the focused element.
+    return !!element;
+  },
+
+  isCommandEnabled(aCommand) {
+    // Handle commands that are not selection-specific.
+    if (aCommand == "downloadsCmd_clearList") {
+      return DownloadsCommon.getData(window).canRemoveFinished;
+    }
+
+    // Other commands are selection-specific.
+    let element = DownloadsView.richListBox.selectedItem;
+    return element && DownloadsView.itemForElement(element)
+                                   .isCommandEnabled(aCommand);
+  },
+
+  doCommand(aCommand) {
+    // If this command is not selection-specific, execute it.
+    if (aCommand in this) {
+      this[aCommand]();
+      return;
+    }
+
+    // Other commands are selection-specific.
+    let element = DownloadsView.richListBox.selectedItem;
+    if (element) {
+      // The doCommand function also checks if the command is enabled.
+      DownloadsView.itemForElement(element).doCommand(aCommand);
+    }
+  },
+
+  onEvent() {},
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Other functions
+
+  updateCommands() {
+    function updateCommandsForObject(object) {
+      for (let name in object) {
+        if (DownloadsViewUI.isCommandName(name)) {
+          goUpdateCommand(name);
+        }
+      }
+    }
+    updateCommandsForObject(this);
+    updateCommandsForObject(DownloadsViewItem.prototype);
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Selection-independent commands
+
+  downloadsCmd_clearList() {
+    DownloadsCommon.getData(window).removeFinished();
+  },
+};
+
+XPCOMUtils.defineConstant(this, "DownloadsViewController", DownloadsViewController);
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsSummary
+
+/**
+ * Manages the summary at the bottom of the downloads panel list if the number
+ * of items in the list exceeds the panels limit.
+ */
+const DownloadsSummary = {
+
+  /**
+   * Sets the active state of the summary. When active, the summary subscribes
+   * to the DownloadsCommon DownloadsSummaryData singleton.
+   *
+   * @param aActive
+   *        Set to true to activate the summary.
+   */
+  set active(aActive) {
+    if (aActive == this._active || !this._summaryNode) {
+      return this._active;
+    }
+    if (aActive) {
+      DownloadsCommon.getSummary(window, DownloadsView.kItemCountLimit)
+                     .refreshView(this);
+    } else {
+      DownloadsFooter.showingSummary = false;
+    }
+
+    return this._active = aActive;
+  },
+
+  /**
+   * Returns the active state of the downloads summary.
+   */
+  get active() {
+    return this._active;
+  },
+
+  _active: false,
+
+  /**
+   * Sets whether or not we show the progress bar.
+   *
+   * @param aShowingProgress
+   *        True if we should show the progress bar.
+   */
+  set showingProgress(aShowingProgress) {
+    if (aShowingProgress) {
+      this._summaryNode.setAttribute("inprogress", "true");
+    } else {
+      this._summaryNode.removeAttribute("inprogress");
+    }
+    // If progress isn't being shown, then we simply do not show the summary.
+    return DownloadsFooter.showingSummary = aShowingProgress;
+  },
+
+  /**
+   * Sets the amount of progress that is visible in the progress bar.
+   *
+   * @param aValue
+   *        A value between 0 and 100 to represent the progress of the
+   *        summarized downloads.
+   */
+  set percentComplete(aValue) {
+    if (this._progressNode) {
+      this._progressNode.setAttribute("value", aValue);
+    }
+    return aValue;
+  },
+
+  /**
+   * Sets the description for the download summary.
+   *
+   * @param aValue
+   *        A string representing the description of the summarized
+   *        downloads.
+   */
+  set description(aValue) {
+    if (this._descriptionNode) {
+      this._descriptionNode.setAttribute("value", aValue);
+      this._descriptionNode.setAttribute("tooltiptext", aValue);
+    }
+    return aValue;
+  },
+
+  /**
+   * Sets the details for the download summary, such as the time remaining,
+   * the amount of bytes transferred, etc.
+   *
+   * @param aValue
+   *        A string representing the details of the summarized
+   *        downloads.
+   */
+  set details(aValue) {
+    if (this._detailsNode) {
+      this._detailsNode.setAttribute("value", aValue);
+      this._detailsNode.setAttribute("tooltiptext", aValue);
+    }
+    return aValue;
+  },
+
+  /**
+   * Focuses the root element of the summary.
+   */
+  focus() {
+    if (this._summaryNode) {
+      this._summaryNode.focus();
+    }
+  },
+
+  /**
+   * Respond to keydown events on the Downloads Summary node.
+   *
+   * @param aEvent
+   *        The keydown event being handled.
+   */
+  onKeyDown(aEvent) {
+    if (aEvent.charCode == " ".charCodeAt(0) ||
+        aEvent.keyCode == KeyEvent.DOM_VK_RETURN) {
+      DownloadsPanel.showDownloadsHistory();
+    }
+  },
+
+  /**
+   * Respond to click events on the Downloads Summary node.
+   *
+   * @param aEvent
+   *        The click event being handled.
+   */
+  onClick(aEvent) {
+    DownloadsPanel.showDownloadsHistory();
+  },
+
+  /**
+   * Element corresponding to the root of the downloads summary.
+   */
+  get _summaryNode() {
+    let node = document.getElementById("downloadsSummary");
+    if (!node) {
+      return null;
+    }
+    delete this._summaryNode;
+    return this._summaryNode = node;
+  },
+
+  /**
+   * Element corresponding to the progress bar in the downloads summary.
+   */
+  get _progressNode() {
+    let node = document.getElementById("downloadsSummaryProgress");
+    if (!node) {
+      return null;
+    }
+    delete this._progressNode;
+    return this._progressNode = node;
+  },
+
+  /**
+   * Element corresponding to the main description of the downloads
+   * summary.
+   */
+  get _descriptionNode() {
+    let node = document.getElementById("downloadsSummaryDescription");
+    if (!node) {
+      return null;
+    }
+    delete this._descriptionNode;
+    return this._descriptionNode = node;
+  },
+
+  /**
+   * Element corresponding to the secondary description of the downloads
+   * summary.
+   */
+  get _detailsNode() {
+    let node = document.getElementById("downloadsSummaryDetails");
+    if (!node) {
+      return null;
+    }
+    delete this._detailsNode;
+    return this._detailsNode = node;
+  }
+};
+
+XPCOMUtils.defineConstant(this, "DownloadsSummary", DownloadsSummary);
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsFooter
+
+/**
+ * Manages events sent to to the footer vbox, which contains both the
+ * DownloadsSummary as well as the "Show All Downloads" button.
+ */
+const DownloadsFooter = {
+
+  /**
+   * Focuses the appropriate element within the footer. If the summary
+   * is visible, focus it. If not, focus the "Show All Downloads"
+   * button.
+   */
+  focus() {
+    if (this._showingSummary) {
+      DownloadsSummary.focus();
+    } else {
+      DownloadsView.downloadsHistory.focus();
+    }
+  },
+
+  _showingSummary: false,
+
+  /**
+   * Sets whether or not the Downloads Summary should be displayed in the
+   * footer. If not, the "Show All Downloads" button is shown instead.
+   */
+  set showingSummary(aValue) {
+    if (this._footerNode) {
+      if (aValue) {
+        this._footerNode.setAttribute("showingsummary", "true");
+      } else {
+        this._footerNode.removeAttribute("showingsummary");
+      }
+      if (!aValue && this._showingSummary) {
+        // Make sure the panel's height shrinks when the summary is hidden.
+        DownloadsPanel.setHeightToFit();
+      }
+      this._showingSummary = aValue;
+    }
+    return aValue;
+  },
+
+  /**
+   * Element corresponding to the footer of the downloads panel.
+   */
+  get _footerNode() {
+    let node = document.getElementById("downloadsFooter");
+    if (!node) {
+      return null;
+    }
+    delete this._footerNode;
+    return this._footerNode = node;
+  }
+};
+
+XPCOMUtils.defineConstant(this, "DownloadsFooter", DownloadsFooter);
+
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsBlockedSubview
+
+/**
+ * Manages the blocked subview that slides in when you click a blocked download.
+ */
+const DownloadsBlockedSubview = {
+
+  get subview() {
+    let subview = document.getElementById("downloadsPanel-blockedSubview");
+    delete this.subview;
+    return this.subview = subview;
+  },
+
+  /**
+   * Elements in the subview.
+   */
+  get elements() {
+    let idSuffixes = [
+      "title",
+      "details1",
+      "details2",
+      "openButton",
+      "deleteButton",
+    ];
+    let elements = idSuffixes.reduce((memo, s) => {
+      memo[s] = document.getElementById("downloadsPanel-blockedSubview-" + s);
+      return memo;
+    }, {});
+    delete this.elements;
+    return this.elements = elements;
+  },
+
+  /**
+   * The multiview that contains both the main view and the subview.
+   */
+  get view() {
+    let view = document.getElementById("downloadsPanel-multiView");
+    delete this.view;
+    return this.view = view;
+  },
+
+  /**
+   * The blocked-download richlistitem element that was clicked to show the
+   * subview.  If the subview is not showing, this is undefined.
+   */
+  element: undefined,
+
+  /**
+   * Slides in the blocked subview.
+   *
+   * @param element
+   *        The blocked-download richlistitem element that was clicked.
+   * @param title
+   *        The title to show in the subview.
+   * @param details
+   *        An array of strings with information about the block.
+   */
+  toggle(element, title, details) {
+    if (this.view.showingSubView) {
+      this.hide();
+      return;
+    }
+
+    this.element = element;
+    element.setAttribute("showingsubview", "true");
+    DownloadsView.subViewOpen = true;
+    DownloadsViewController.updateCommands();
+
+    let e = this.elements;
+    let s = DownloadsCommon.strings;
+    e.title.textContent = title;
+    e.details1.textContent = details[0];
+    e.details2.textContent = details[1];
+    e.openButton.label = s.unblockButtonOpen;
+    e.deleteButton.label = s.unblockButtonConfirmBlock;
+
+    let verdict = element.getAttribute("verdict");
+    this.subview.setAttribute("verdict", verdict);
+    this.subview.addEventListener("ViewHiding", this);
+
+    this.view.showSubView(this.subview.id);
+
+    // Without this, the mainView is more narrow than the panel once all
+    // downloads are removed from the panel.
+    document.getElementById("downloadsPanel-mainView").style.minWidth =
+      window.getComputedStyle(this.view).width;
+  },
+
+  handleEvent(event) {
+    switch (event.type) {
+      case "ViewHiding":
+        this.subview.removeEventListener(event.type, this);
+        this.element.removeAttribute("showingsubview");
+        DownloadsView.subViewOpen = false;
+        delete this.element;
+        break;
+      default:
+        DownloadsCommon.log("Unhandled DownloadsBlockedSubview event: " +
+                            event.type);
+        break;
+    }
+  },
+
+  /**
+   * Slides out the blocked subview and shows the main view.
+   */
+  hide() {
+    this.view.showMainView();
+    // The point of this is to focus the proper element in the panel now that
+    // the main view is showing again.  showPanel handles that.
+    DownloadsPanel.showPanel();
+  },
+
+  /**
+   * Deletes the download and hides the entire panel.
+   */
+  confirmBlock() {
+    goDoCommand("cmd_delete");
+    DownloadsPanel.hidePanel();
+  },
+};
+
+XPCOMUtils.defineConstant(this, "DownloadsBlockedSubview",
+                          DownloadsBlockedSubview);
diff --git a/browser/components/downloads/content/downloadsOverlay.xul b/browser/components/downloads/content/downloadsOverlay.xul
new file mode 100644
index 000000000..9fe2ee022
--- /dev/null
+++ b/browser/components/downloads/content/downloadsOverlay.xul
@@ -0,0 +1,210 @@
+<?xml version="1.0"?>
+# -*- Mode: HTML; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+# vim: set ts=2 et sw=2 tw=80:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+<?xml-stylesheet href="chrome://browser/content/downloads/downloads.css"?>
+<?xml-stylesheet href="chrome://browser/skin/downloads/downloads.css"?>
+
+<!DOCTYPE overlay SYSTEM "chrome://browser/locale/downloads/downloads.dtd">
+
+<overlay xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+         id="downloadsOverlay">
+
+  <commandset>
+    <command id="downloadsCmd_doDefault"
+             oncommand="goDoCommand('downloadsCmd_doDefault')"/>
+    <command id="downloadsCmd_pauseResume"
+             oncommand="goDoCommand('downloadsCmd_pauseResume')"/>
+    <command id="downloadsCmd_cancel"
+             oncommand="goDoCommand('downloadsCmd_cancel')"/>
+    <command id="downloadsCmd_unblock"
+             oncommand="goDoCommand('downloadsCmd_unblock')"/>
+    <command id="downloadsCmd_chooseUnblock"
+             oncommand="goDoCommand('downloadsCmd_chooseUnblock')"/>
+    <command id="downloadsCmd_unblockAndOpen"
+             oncommand="goDoCommand('downloadsCmd_unblockAndOpen')"/>
+    <command id="downloadsCmd_confirmBlock"
+             oncommand="goDoCommand('downloadsCmd_confirmBlock')"/>
+    <command id="downloadsCmd_open"
+             oncommand="goDoCommand('downloadsCmd_open')"/>
+    <command id="downloadsCmd_show"
+             oncommand="goDoCommand('downloadsCmd_show')"/>
+    <command id="downloadsCmd_retry"
+             oncommand="goDoCommand('downloadsCmd_retry')"/>
+    <command id="downloadsCmd_openReferrer"
+             oncommand="goDoCommand('downloadsCmd_openReferrer')"/>
+    <command id="downloadsCmd_copyLocation"
+             oncommand="goDoCommand('downloadsCmd_copyLocation')"/>
+    <command id="downloadsCmd_clearList"
+             oncommand="goDoCommand('downloadsCmd_clearList')"/>
+  </commandset>
+
+  <popupset id="mainPopupSet">
+    <!-- The panel has level="top" to ensure that it is never hidden by the
+         taskbar on Windows.  See bug 672365.  For accessibility to screen
+         readers, we use a label on the panel instead of the anchor because the
+         panel can also be displayed without an anchor. -->
+    <panel id="downloadsPanel"
+           aria-label="&downloads.title;"
+           role="group"
+           type="arrow"
+           orient="vertical"
+           level="top"
+           onpopupshown="DownloadsPanel.onPopupShown(event);"
+           onpopuphidden="DownloadsPanel.onPopupHidden(event);">
+      <!-- The following popup menu should be a child of the panel element,
+           otherwise flickering may occur when the cursor is moved over the area
+           of a disabled menu item that overlaps the panel.  See bug 492960. -->
+      <menupopup id="downloadsContextMenu"
+                 onpopupshown="DownloadsView.onContextPopupShown(event);"
+                 onpopuphidden="DownloadsView.onContextPopupHidden(event);"
+                 class="download-state">
+        <menuitem command="downloadsCmd_pauseResume"
+                  class="downloadPauseMenuItem"
+                  label="&cmd.pause.label;"
+                  accesskey="&cmd.pause.accesskey;"/>
+        <menuitem command="downloadsCmd_pauseResume"
+                  class="downloadResumeMenuItem"
+                  label="&cmd.resume.label;"
+                  accesskey="&cmd.resume.accesskey;"/>
+        <menuitem command="downloadsCmd_cancel"
+                  class="downloadCancelMenuItem"
+                  label="&cmd.cancel.label;"
+                  accesskey="&cmd.cancel.accesskey;"/>
+        <menuitem command="downloadsCmd_unblock"
+                  class="downloadUnblockMenuItem"
+                  label="&cmd.unblock2.label;"
+                  accesskey="&cmd.unblock2.accesskey;"/>
+        <menuitem command="cmd_delete"
+                  class="downloadRemoveFromHistoryMenuItem"
+                  label="&cmd.removeFromHistory.label;"
+                  accesskey="&cmd.removeFromHistory.accesskey;"/>
+        <menuitem command="downloadsCmd_show"
+                  class="downloadShowMenuItem"
+#ifdef XP_MACOSX
+                  label="&cmd.showMac.label;"
+                  accesskey="&cmd.showMac.accesskey;"
+#else
+                  label="&cmd.show.label;"
+                  accesskey="&cmd.show.accesskey;"
+#endif
+                  />
+
+        <menuseparator class="downloadCommandsSeparator"/>
+
+        <menuitem command="downloadsCmd_openReferrer"
+                  label="&cmd.goToDownloadPage.label;"
+                  accesskey="&cmd.goToDownloadPage.accesskey;"/>
+        <menuitem command="downloadsCmd_copyLocation"
+                  label="&cmd.copyDownloadLink.label;"
+                  accesskey="&cmd.copyDownloadLink.accesskey;"/>
+
+        <menuseparator/>
+
+        <menuitem command="downloadsCmd_clearList"
+                  label="&cmd.clearList2.label;"
+                  accesskey="&cmd.clearList2.accesskey;"/>
+      </menupopup>
+
+      <panelmultiview id="downloadsPanel-multiView"
+                      mainViewId="downloadsPanel-mainView"
+                      align="stretch">
+
+        <panelview id="downloadsPanel-mainView"
+                   flex="1"
+                   align="stretch">
+          <richlistbox id="downloadsListBox"
+                       context="downloadsContextMenu"
+                       onmouseover="DownloadsView.onDownloadMouseOver(event);"
+                       onmouseout="DownloadsView.onDownloadMouseOut(event);"
+                       oncontextmenu="DownloadsView.onDownloadContextMenu(event);"
+                       ondragstart="DownloadsView.onDownloadDragStart(event);"/>
+          <description id="emptyDownloads"
+                       mousethrough="always">
+             &downloadsPanelEmpty.label;
+          </description>
+          <spacer flex="1"/>
+          <vbox id="downloadsFooter"
+                class="downloadsPanelFooter">
+            <stack>
+              <hbox id="downloadsSummary"
+                    align="center"
+                    orient="horizontal"
+                    onkeydown="DownloadsSummary.onKeyDown(event);"
+                    onclick="DownloadsSummary.onClick(event);">
+                <image class="downloadTypeIcon" />
+                <vbox pack="center"
+                      class="downloadContainer"
+                      style="width: &downloadDetails.width;">
+                  <description id="downloadsSummaryDescription"
+                               style="min-width: &downloadsSummary.minWidth2;"/>
+                  <progressmeter id="downloadsSummaryProgress"
+                                 class="downloadProgress"
+                                 min="0"
+                                 max="100"
+                                 mode="normal" />
+                  <description id="downloadsSummaryDetails"
+                               crop="end"/>
+                </vbox>
+              </hbox>
+              <hbox id="downloadsFooterButtons">
+                <button id="downloadsHistory"
+                        class="downloadsPanelFooterButton"
+                        label="&downloadsHistory.label;"
+                        accesskey="&downloadsHistory.accesskey;"
+                        flex="1"
+                        oncommand="DownloadsPanel.showDownloadsHistory();"/>
+                <toolbarseparator id="downloadsFooterButtonsSplitter"
+                        class="downloadsDropmarkerSplitter"/>
+                <button id="downloadsFooterDropmarker"
+                        class="downloadsPanelFooterButton downloadsDropmarker"
+                        type="menu">
+                  <menupopup id="downloadSubPanel"
+                             onpopupshowing="DownloadsPanel.onFooterPopupShowing(event);"
+                             onpopuphidden="DownloadsPanel.onFooterPopupHidden(event);"
+                             position="after_end">
+                    <menuitem id="downloadsDropdownItemClearList"
+                              command="downloadsCmd_clearList"
+                              label="&cmd.clearList2.label;"/>
+                    <menuitem id="downloadsDropdownItemOpenDownloadsFolder"
+                              oncommand="DownloadsPanel.openDownloadsFolder();"
+                              label="&openDownloadsFolder.label;"/>
+                  </menupopup>
+                </button>
+              </hbox>
+            </stack>
+          </vbox>
+        </panelview>
+
+        <panelview id="downloadsPanel-blockedSubview"
+                   orient="vertical"
+                   flex="1">
+          <description id="downloadsPanel-blockedSubview-title"/>
+          <description id="downloadsPanel-blockedSubview-details1"/>
+          <description id="downloadsPanel-blockedSubview-details2"/>
+          <spacer flex="1"/>
+          <hbox id="downloadsPanel-blockedSubview-buttons"
+                class="downloadsPanelFooter"
+                align="stretch">
+            <button id="downloadsPanel-blockedSubview-openButton"
+                    class="downloadsPanelFooterButton"
+                    command="downloadsCmd_unblockAndOpen"
+                    flex="1"/>
+            <toolbarseparator/>
+            <button id="downloadsPanel-blockedSubview-deleteButton"
+                    class="downloadsPanelFooterButton"
+                    oncommand="DownloadsBlockedSubview.confirmBlock();"
+                    default="true"
+                    flex="1"/>
+          </hbox>
+        </panelview>
+
+      </panelmultiview>
+
+    </panel>
+  </popupset>
+</overlay>
diff --git a/browser/components/downloads/content/indicator.js b/browser/components/downloads/content/indicator.js
new file mode 100644
index 000000000..4c22a6e5d
--- /dev/null
+++ b/browser/components/downloads/content/indicator.js
@@ -0,0 +1,606 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Handles the indicator that displays the progress of ongoing downloads, which
+ * is also used as the anchor for the downloads panel.
+ *
+ * This module includes the following constructors and global objects:
+ *
+ * DownloadsButton
+ * Main entry point for the downloads indicator.  Depending on how the toolbars
+ * have been customized, this object determines if we should show a fully
+ * functional indicator, a placeholder used during customization and in the
+ * customization palette, or a neutral view as a temporary anchor for the
+ * downloads panel.
+ *
+ * DownloadsIndicatorView
+ * Builds and updates the actual downloads status widget, responding to changes
+ * in the global status data, or provides a neutral view if the indicator is
+ * removed from the toolbars and only used as a temporary anchor.  In addition,
+ * handles the user interaction events raised by the widget.
+ */
+
+"use strict";
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsButton
+
+/**
+ * Main entry point for the downloads indicator.  Depending on how the toolbars
+ * have been customized, this object determines if we should show a fully
+ * functional indicator, a placeholder used during customization and in the
+ * customization palette, or a neutral view as a temporary anchor for the
+ * downloads panel.
+ */
+const DownloadsButton = {
+  /**
+   * Location of the indicator overlay.
+   */
+  get kIndicatorOverlay() {
+    return "chrome://browser/content/downloads/indicatorOverlay.xul";
+  },
+
+  /**
+   * Returns a reference to the downloads button position placeholder, or null
+   * if not available because it has been removed from the toolbars.
+   */
+  get _placeholder() {
+    return document.getElementById("downloads-button");
+  },
+
+  /**
+   * This function is called asynchronously just after window initialization.
+   *
+   * NOTE: This function should limit the input/output it performs to improve
+   *       startup time.
+   */
+  initializeIndicator() {
+    DownloadsIndicatorView.ensureInitialized();
+  },
+
+  /**
+   * Indicates whether toolbar customization is in progress.
+   */
+  _customizing: false,
+
+  /**
+   * This function is called when toolbar customization starts.
+   *
+   * During customization, we never show the actual download progress indication
+   * or the event notifications, but we show a neutral placeholder.  The neutral
+   * placeholder is an ordinary button defined in the browser window that can be
+   * moved freely between the toolbars and the customization palette.
+   */
+  customizeStart() {
+    // Prevent the indicator from being displayed as a temporary anchor
+    // during customization, even if requested using the getAnchor method.
+    this._customizing = true;
+    this._anchorRequested = false;
+  },
+
+  /**
+   * This function is called when toolbar customization ends.
+   */
+  customizeDone() {
+    this._customizing = false;
+    DownloadsIndicatorView.afterCustomize();
+  },
+
+  /**
+   * Determines the position where the indicator should appear, and moves its
+   * associated element to the new position.
+   *
+   * @return Anchor element, or null if the indicator is not visible.
+   */
+  _getAnchorInternal() {
+    let indicator = DownloadsIndicatorView.indicator;
+    if (!indicator) {
+      // Exit now if the indicator overlay isn't loaded yet, or if the button
+      // is not in the document.
+      return null;
+    }
+
+    indicator.open = this._anchorRequested;
+
+    let widget = CustomizableUI.getWidget("downloads-button")
+                               .forWindow(window);
+     // Determine if the indicator is located on an invisible toolbar.
+     if (!isElementVisible(indicator.parentNode) && !widget.overflowed) {
+       return null;
+     }
+
+    return DownloadsIndicatorView.indicatorAnchor;
+  },
+
+  /**
+   * Checks whether the indicator is, or will soon be visible in the browser
+   * window.
+   *
+   * @param aCallback
+   *        Called once the indicator overlay has loaded. Gets a boolean
+   *        argument representing the indicator visibility.
+   */
+  checkIsVisible(aCallback) {
+    DownloadsOverlayLoader.ensureOverlayLoaded(this.kIndicatorOverlay, () => {
+      if (!this._placeholder) {
+        aCallback(false);
+      } else {
+        let element = DownloadsIndicatorView.indicator || this._placeholder;
+        aCallback(isElementVisible(element.parentNode));
+      }
+    });
+  },
+
+  /**
+   * Indicates whether we should try and show the indicator temporarily as an
+   * anchor for the panel, even if the indicator would be hidden by default.
+   */
+  _anchorRequested: false,
+
+  /**
+   * Ensures that there is an anchor available for the panel.
+   *
+   * @param aCallback
+   *        Called when the anchor is available, passing the element where the
+   *        panel should be anchored, or null if an anchor is not available (for
+   *        example because both the tab bar and the navigation bar are hidden).
+   */
+  getAnchor(aCallback) {
+    // Do not allow anchoring the panel to the element while customizing.
+    if (this._customizing) {
+      aCallback(null);
+      return;
+    }
+
+    DownloadsOverlayLoader.ensureOverlayLoaded(this.kIndicatorOverlay, () => {
+      this._anchorRequested = true;
+      aCallback(this._getAnchorInternal());
+    });
+  },
+
+  /**
+   * Allows the temporary anchor to be hidden.
+   */
+  releaseAnchor() {
+    this._anchorRequested = false;
+    this._getAnchorInternal();
+  },
+
+  get _tabsToolbar() {
+    delete this._tabsToolbar;
+    return this._tabsToolbar = document.getElementById("TabsToolbar");
+  },
+
+  get _navBar() {
+    delete this._navBar;
+    return this._navBar = document.getElementById("nav-bar");
+  }
+};
+
+Object.defineProperty(this, "DownloadsButton", {
+  value: DownloadsButton,
+  enumerable: true,
+  writable: false
+});
+
+////////////////////////////////////////////////////////////////////////////////
+//// DownloadsIndicatorView
+
+/**
+ * Builds and updates the actual downloads status widget, responding to changes
+ * in the global status data, or provides a neutral view if the indicator is
+ * removed from the toolbars and only used as a temporary anchor.  In addition,
+ * handles the user interaction events raised by the widget.
+ */
+const DownloadsIndicatorView = {
+  /**
+   * True when the view is connected with the underlying downloads data.
+   */
+  _initialized: false,
+
+  /**
+   * True when the user interface elements required to display the indicator
+   * have finished loading in the browser window, and can be referenced.
+   */
+  _operational: false,
+
+  /**
+   * Prepares the downloads indicator to be displayed.
+   */
+  ensureInitialized() {
+    if (this._initialized) {
+      return;
+    }
+    this._initialized = true;
+
+    window.addEventListener("unload", this.onWindowUnload, false);
+    DownloadsCommon.getIndicatorData(window).addView(this);
+  },
+
+  /**
+   * Frees the internal resources related to the indicator.
+   */
+  ensureTerminated() {
+    if (!this._initialized) {
+      return;
+    }
+    this._initialized = false;
+
+    window.removeEventListener("unload", this.onWindowUnload, false);
+    DownloadsCommon.getIndicatorData(window).removeView(this);
+
+    // Reset the view properties, so that a neutral indicator is displayed if we
+    // are visible only temporarily as an anchor.
+    this.counter = "";
+    this.percentComplete = 0;
+    this.paused = false;
+    this.attention = DownloadsCommon.ATTENTION_NONE;
+  },
+
+  /**
+   * Ensures that the user interface elements required to display the indicator
+   * are loaded, then invokes the given callback.
+   */
+  _ensureOperational(aCallback) {
+    if (this._operational) {
+      if (aCallback) {
+        aCallback();
+      }
+      return;
+    }
+
+    // If we don't have a _placeholder, there's no chance that the overlay
+    // will load correctly: bail (and don't set _operational to true!)
+    if (!DownloadsButton._placeholder) {
+      return;
+    }
+
+    DownloadsOverlayLoader.ensureOverlayLoaded(
+      DownloadsButton.kIndicatorOverlay,
+      () => {
+        this._operational = true;
+
+        // If the view is initialized, we need to update the elements now that
+        // they are finally available in the document.
+        if (this._initialized) {
+          DownloadsCommon.getIndicatorData(window).refreshView(this);
+        }
+
+        if (aCallback) {
+          aCallback();
+        }
+      });
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Direct control functions
+
+  /**
+   * Set while we are waiting for a notification to fade out.
+   */
+  _notificationTimeout: null,
+
+  /**
+   * Check if the panel containing aNode is open.
+   * @param aNode
+   *        the node whose panel we're interested in.
+   */
+  _isAncestorPanelOpen(aNode) {
+    while (aNode && aNode.localName != "panel") {
+      aNode = aNode.parentNode;
+    }
+    return aNode && aNode.state == "open";
+  },
+
+  /**
+   * If the status indicator is visible in its assigned position, shows for a
+   * brief time a visual notification of a relevant event, like a new download.
+   *
+   * @param aType
+   *        Set to "start" for new downloads, "finish" for completed downloads.
+   */
+  showEventNotification(aType) {
+    if (!this._initialized) {
+      return;
+    }
+
+    if (!DownloadsCommon.animateNotifications) {
+      return;
+    }
+
+    // No need to show visual notification if the panel is visible.
+    if (DownloadsPanel.isPanelShowing) {
+      return;
+    }
+
+    let anchor = DownloadsButton._placeholder;
+    let widgetGroup = CustomizableUI.getWidget("downloads-button");
+    let widget = widgetGroup.forWindow(window);
+    if (widget.overflowed || widgetGroup.areaType == CustomizableUI.TYPE_MENU_PANEL) {
+      if (anchor && this._isAncestorPanelOpen(anchor)) {
+        // If the containing panel is open, don't do anything, because the
+        // notification would appear under the open panel. See
+        // https://bugzilla.mozilla.org/show_bug.cgi?id=984023
+        return;
+      }
+
+      // Otherwise, try to use the anchor of the panel:
+      anchor = widget.anchor;
+    }
+    if (!anchor || !isElementVisible(anchor.parentNode)) {
+      // Our container isn't visible, so can't show the animation:
+      return;
+    }
+
+    if (this._notificationTimeout) {
+      clearTimeout(this._notificationTimeout);
+    }
+
+    // The notification element is positioned to show in the same location as
+    // the downloads button. It's not in the downloads button itself in order to
+    // be able to anchor the notification elsewhere if required, and to ensure
+    // the notification isn't clipped by overflow properties of the anchor's
+    // container.
+    let notifier = this.notifier;
+    if (notifier.style.transform == '') {
+      let anchorRect = anchor.getBoundingClientRect();
+      let notifierRect = notifier.getBoundingClientRect();
+      let topDiff = anchorRect.top - notifierRect.top;
+      let leftDiff = anchorRect.left - notifierRect.left;
+      let heightDiff = anchorRect.height - notifierRect.height;
+      let widthDiff = anchorRect.width - notifierRect.width;
+      let translateX = (leftDiff + .5 * widthDiff) + "px";
+      let translateY = (topDiff + .5 * heightDiff) + "px";
+      notifier.style.transform = "translate(" +  translateX + ", " + translateY + ")";
+    }
+    notifier.setAttribute("notification", aType);
+    this._notificationTimeout = setTimeout(() => {
+      notifier.removeAttribute("notification");
+      notifier.style.transform = '';
+    }, 1000);
+  },
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// Callback functions from DownloadsIndicatorData
+
+  /**
+   * Indicates whether the indicator should be shown because there are some
+   * downloads to be displayed.
+   */
+  set hasDownloads(aValue) {
+    if (this._hasDownloads != aValue || (!this._operational && aValue)) {
+      this._hasDownloads = aValue;
+
+      // If there is at least one download, ensure that the view elements are
+      if (aValue) {
+        this._ensureOperational();
+      }
+    }
+    return aValue;
+  },
+  get hasDownloads() {
+    return this._hasDownloads;
+  },
+  _hasDownloads: false,
+
+  /**
+   * Status text displayed in the indicator.  If this is set to an empty value,
+   * then the small downloads icon is displayed instead of the text.
+   */
+  set counter(aValue) {
+    if (!this._operational) {
+      return this._counter;
+    }
+
+    if (this._counter !== aValue) {
+      this._counter = aValue;
+      if (this._counter)
+        this.indicator.setAttribute("counter", "true");
+      else
+        this.indicator.removeAttribute("counter");
+      // We have to set the attribute instead of using the property because the
+      // XBL binding isn't applied if the element is invisible for any reason.
+      this._indicatorCounter.setAttribute("value", aValue);
+    }
+    return aValue;
+  },
+  _counter: null,
+
+  /**
+   * Progress indication to display, from 0 to 100, or -1 if unknown.  The
+   * progress bar is hidden if the current progress is unknown and no status
+   * text is set in the "counter" property.
+   */
+  set percentComplete(aValue) {
+    if (!this._operational) {
+      return this._percentComplete;
+    }
+
+    if (this._percentComplete !== aValue) {
+      this._percentComplete = aValue;
+      if (this._percentComplete >= 0)
+        this.indicator.setAttribute("progress", "true");
+      else
+        this.indicator.removeAttribute("progress");
+      // We have to set the attribute instead of using the property because the
+      // XBL binding isn't applied if the element is invisible for any reason.
+      this._indicatorProgress.setAttribute("value", Math.max(aValue, 0));
+    }
+    return aValue;
+  },
+  _percentComplete: null,
+
+  /**
+   * Indicates whether the progress won't advance because of a paused state.
+   * Setting this property forces a paused progress bar to be displayed, even if
+   * the current progress information is unavailable.
+   */
+  set paused(aValue) {
+    if (!this._operational) {
+      return this._paused;
+    }
+
+    if (this._paused != aValue) {
+      this._paused = aValue;
+      if (this._paused) {
+        this.indicator.setAttribute("paused", "true")
+      } else {
+        this.indicator.removeAttribute("paused");
+      }
+    }
+    return aValue;
+  },
+  _paused: false,
+
+  /**
+   * Set when the indicator should draw user attention to itself.
+   */
+  set attention(aValue) {
+    if (!this._operational) {
+      return this._attention;
+    }
+
+    if (this._attention != aValue) {
+      this._attention = aValue;
+
+      // Check if the downloads button is in the menu panel, to determine which
+      // button needs to get a badge.
+      let widgetGroup = CustomizableUI.getWidget("downloads-button");
+      let inMenu = widgetGroup.areaType == CustomizableUI.TYPE_MENU_PANEL;
+
+      if (aValue == DownloadsCommon.ATTENTION_NONE) {
+        this.indicator.removeAttribute("attention");
+        if (inMenu) {
+          gMenuButtonBadgeManager.removeBadge(gMenuButtonBadgeManager.BADGEID_DOWNLOAD);
+        }
+      } else {
+        this.indicator.setAttribute("attention", aValue);
+        if (inMenu) {
+          let badgeClass = "download-" + aValue;
+          gMenuButtonBadgeManager.addBadge(gMenuButtonBadgeManager.BADGEID_DOWNLOAD, badgeClass);
+        }
+      }
+    }
+    return aValue;
+  },
+  _attention: DownloadsCommon.ATTENTION_NONE,
+
+  //////////////////////////////////////////////////////////////////////////////
+  //// User interface event functions
+
+  onWindowUnload() {
+    // This function is registered as an event listener, we can't use "this".
+    DownloadsIndicatorView.ensureTerminated();
+  },
+
+  onCommand(aEvent) {
+    // If the downloads button is in the menu panel, open the Library
+    let widgetGroup = CustomizableUI.getWidget("downloads-button");
+    if (widgetGroup.areaType == CustomizableUI.TYPE_MENU_PANEL) {
+      DownloadsPanel.showDownloadsHistory();
+    } else {
+      DownloadsPanel.showPanel();
+    }
+
+    aEvent.stopPropagation();
+  },
+
+  onDragOver(aEvent) {
+    browserDragAndDrop.dragOver(aEvent);
+  },
+
+  onDrop(aEvent) {
+    let dt = aEvent.dataTransfer;
+    // If dragged item is from our source, do not try to
+    // redownload already downloaded file.
+    if (dt.mozGetDataAt("application/x-moz-file", 0))
+      return;
+
+    let links = browserDragAndDrop.dropLinks(aEvent);
+    if (!links.length)
+      return;
+    let sourceDoc = dt.mozSourceNode ? dt.mozSourceNode.ownerDocument : document;
+    let handled = false;
+    for (let link of links) {
+      if (link.url.startsWith("about:"))
+        continue;
+      saveURL(link.url, link.name, null, true, true, null, sourceDoc);
+      handled = true;
+    }
+    if (handled) {
+      aEvent.preventDefault();
+    }
+  },
+
+  _indicator: null,
+  __indicatorCounter: null,
+  __indicatorProgress: null,
+
+  /**
+   * Returns a reference to the main indicator element, or null if the element
+   * is not present in the browser window yet.
+   */
+  get indicator() {
+    if (this._indicator) {
+      return this._indicator;
+    }
+
+    let indicator = document.getElementById("downloads-button");
+    if (!indicator || indicator.getAttribute("indicator") != "true") {
+      return null;
+    }
+
+    return this._indicator = indicator;
+  },
+
+  get indicatorAnchor() {
+    let widget = CustomizableUI.getWidget("downloads-button")
+                               .forWindow(window);
+    if (widget.overflowed) {
+      return widget.anchor;
+    }
+    return document.getElementById("downloads-indicator-anchor");
+  },
+
+  get _indicatorCounter() {
+    return this.__indicatorCounter ||
+      (this.__indicatorCounter = document.getElementById("downloads-indicator-counter"));
+  },
+
+  get _indicatorProgress() {
+    return this.__indicatorProgress ||
+      (this.__indicatorProgress = document.getElementById("downloads-indicator-progress"));
+  },
+
+  get notifier() {
+    return this._notifier ||
+      (this._notifier = document.getElementById("downloads-notification-anchor"));
+  },
+
+  _onCustomizedAway() {
+    this._indicator = null;
+    this.__indicatorCounter = null;
+    this.__indicatorProgress = null;
+  },
+
+  afterCustomize() {
+    // If the cached indicator is not the one currently in the document,
+    // invalidate our references
+    if (this._indicator != document.getElementById("downloads-button")) {
+      this._onCustomizedAway();
+      this._operational = false;
+      this.ensureTerminated();
+      this.ensureInitialized();
+    }
+  },
+};
+
+Object.defineProperty(this, "DownloadsIndicatorView", {
+  value: DownloadsIndicatorView,
+  enumerable: true,
+  writable: false
+});
diff --git a/browser/components/downloads/content/indicatorOverlay.xul b/browser/components/downloads/content/indicatorOverlay.xul
new file mode 100644
index 000000000..07987c88c
--- /dev/null
+++ b/browser/components/downloads/content/indicatorOverlay.xul
@@ -0,0 +1,36 @@
+<?xml version="1.0"?>
+<!-- -*- Mode: HTML; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- -->
+<!-- vim: set ts=2 et sw=2 tw=80: -->
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this file,
+   - You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!DOCTYPE overlay [
+  <!ENTITY % browserDTD SYSTEM "chrome://browser/locale/browser.dtd" >
+  %browserDTD;
+]>
+
+<overlay xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+         id="indicatorOverlay">
+
+  <!-- We dynamically add the stack with the progress meter and notification icon,
+       originally loaded lazily because of performance reasons, to the existing
+       downloads-button. -->
+  <toolbarbutton id="downloads-button" indicator="true">
+    <!-- The panel's anchor area is smaller than the outer button, but must
+         always be visible and must not move or resize when the indicator
+         state changes, otherwise the panel could change its position or lose
+         its arrow unexpectedly. -->
+    <stack id="downloads-indicator-anchor"
+           consumeanchor="downloads-button">
+      <vbox id="downloads-indicator-progress-area" pack="center">
+        <description id="downloads-indicator-counter"/>
+        <progressmeter id="downloads-indicator-progress" class="plain"
+                       min="0" max="100"/>
+      </vbox>
+      <vbox id="downloads-indicator-icon"/>
+    </stack>
+  </toolbarbutton>
+</overlay>