Add m-esr52 at 52.6.0

3 files changed, 1345 insertions, 0 deletions

diff --git a/browser/components/sessionstore/content/aboutSessionRestore.js b/browser/components/sessionstore/content/aboutSessionRestore.js
new file mode 100644
index 000000000..cc8d2da0b
--- /dev/null
+++ b/browser/components/sessionstore/content/aboutSessionRestore.js
@@ -0,0 +1,362 @@
+/* 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/. */
+
+"use strict";
+
+var {classes: Cc, interfaces: Ci, utils: Cu} = Components;
+
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "AppConstants",
+  "resource://gre/modules/AppConstants.jsm");
+
+var gStateObject;
+var gTreeData;
+
+// Page initialization
+
+window.onload = function() {
+  // pages used by this script may have a link that needs to be updated to
+  // the in-product link.
+  let anchor = document.getElementById("linkMoreTroubleshooting");
+  if (anchor) {
+    let baseURL = Services.urlFormatter.formatURLPref("app.support.baseURL");
+    anchor.setAttribute("href", baseURL + "troubleshooting");
+  }
+
+  // wire up click handlers for the radio buttons if they exist.
+  for (let radioId of ["radioRestoreAll", "radioRestoreChoose"]) {
+    let button = document.getElementById(radioId);
+    if (button) {
+      button.addEventListener("click", updateTabListVisibility);
+    }
+  }
+
+  // the crashed session state is kept inside a textbox so that SessionStore picks it up
+  // (for when the tab is closed or the session crashes right again)
+  var sessionData = document.getElementById("sessionData");
+  if (!sessionData.value) {
+    document.getElementById("errorTryAgain").disabled = true;
+    return;
+  }
+
+  gStateObject = JSON.parse(sessionData.value);
+
+  // make sure the data is tracked to be restored in case of a subsequent crash
+  var event = document.createEvent("UIEvents");
+  event.initUIEvent("input", true, true, window, 0);
+  sessionData.dispatchEvent(event);
+
+  initTreeView();
+
+  document.getElementById("errorTryAgain").focus();
+};
+
+function isTreeViewVisible() {
+  let tabList = document.querySelector(".tree-container");
+  return tabList.hasAttribute("available");
+}
+
+function initTreeView() {
+  // If we aren't visible we initialize as we are made visible (and it's OK
+  // to initialize multiple times)
+  if (!isTreeViewVisible()) {
+    return;
+  }
+  var tabList = document.getElementById("tabList");
+  var winLabel = tabList.getAttribute("_window_label");
+
+  gTreeData = [];
+  gStateObject.windows.forEach(function(aWinData, aIx) {
+    var winState = {
+      label: winLabel.replace("%S", (aIx + 1)),
+      open: true,
+      checked: true,
+      ix: aIx
+    };
+    winState.tabs = aWinData.tabs.map(function(aTabData) {
+      var entry = aTabData.entries[aTabData.index - 1] || { url: "about:blank" };
+      var iconURL = aTabData.image || null;
+      // don't initiate a connection just to fetch a favicon (see bug 462863)
+      if (/^https?:/.test(iconURL))
+        iconURL = "moz-anno:favicon:" + iconURL;
+      return {
+        label: entry.title || entry.url,
+        checked: true,
+        src: iconURL,
+        parent: winState
+      };
+    });
+    gTreeData.push(winState);
+    for (let tab of winState.tabs)
+      gTreeData.push(tab);
+  }, this);
+
+  tabList.view = treeView;
+  tabList.view.selection.select(0);
+}
+
+// User actions
+function updateTabListVisibility() {
+  let tabList = document.querySelector(".tree-container");
+  let container = document.querySelector(".container");
+  if (document.getElementById("radioRestoreChoose").checked) {
+    tabList.setAttribute("available", "true");
+    container.classList.add("restore-chosen");
+  } else {
+    tabList.removeAttribute("available");
+    container.classList.remove("restore-chosen");
+  }
+  initTreeView();
+}
+
+function restoreSession() {
+  Services.obs.notifyObservers(null, "sessionstore-initiating-manual-restore", "");
+  document.getElementById("errorTryAgain").disabled = true;
+
+  if (isTreeViewVisible()) {
+    if (!gTreeData.some(aItem => aItem.checked)) {
+      // This should only be possible when we have no "cancel" button, and thus
+      // the "Restore session" button always remains enabled.  In that case and
+      // when nothing is selected, we just want a new session.
+      startNewSession();
+      return;
+    }
+
+    // remove all unselected tabs from the state before restoring it
+    var ix = gStateObject.windows.length - 1;
+    for (var t = gTreeData.length - 1; t >= 0; t--) {
+      if (treeView.isContainer(t)) {
+        if (gTreeData[t].checked === 0)
+          // this window will be restored partially
+          gStateObject.windows[ix].tabs =
+            gStateObject.windows[ix].tabs.filter((aTabData, aIx) =>
+                                                   gTreeData[t].tabs[aIx].checked);
+        else if (!gTreeData[t].checked)
+          // this window won't be restored at all
+          gStateObject.windows.splice(ix, 1);
+        ix--;
+      }
+    }
+  }
+  var stateString = JSON.stringify(gStateObject);
+
+  var ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
+  var top = getBrowserWindow();
+
+  // if there's only this page open, reuse the window for restoring the session
+  if (top.gBrowser.tabs.length == 1) {
+    ss.setWindowState(top, stateString, true);
+    return;
+  }
+
+  // restore the session into a new window and close the current tab
+  var newWindow = top.openDialog(top.location, "_blank", "chrome,dialog=no,all");
+
+  var obs = Cc["@mozilla.org/observer-service;1"].getService(Ci.nsIObserverService);
+  obs.addObserver(function observe(win, topic) {
+    if (win != newWindow) {
+      return;
+    }
+
+    obs.removeObserver(observe, topic);
+    ss.setWindowState(newWindow, stateString, true);
+
+    var tabbrowser = top.gBrowser;
+    var tabIndex = tabbrowser.getBrowserIndexForDocument(document);
+    tabbrowser.removeTab(tabbrowser.tabs[tabIndex]);
+  }, "browser-delayed-startup-finished", false);
+}
+
+function startNewSession() {
+  var prefBranch = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);
+  if (prefBranch.getIntPref("browser.startup.page") == 0)
+    getBrowserWindow().gBrowser.loadURI("about:blank");
+  else
+    getBrowserWindow().BrowserHome();
+}
+
+function onListClick(aEvent) {
+  // don't react to right-clicks
+  if (aEvent.button == 2)
+    return;
+
+  var cell = treeView.treeBox.getCellAt(aEvent.clientX, aEvent.clientY);
+  if (cell.col) {
+    // Restore this specific tab in the same window for middle/double/accel clicking
+    // on a tab's title.
+    let accelKey = AppConstants.platform == "macosx" ?
+                   aEvent.metaKey :
+                   aEvent.ctrlKey;
+    if ((aEvent.button == 1 || aEvent.button == 0 && aEvent.detail == 2 || accelKey) &&
+        cell.col.id == "title" &&
+        !treeView.isContainer(cell.row)) {
+      restoreSingleTab(cell.row, aEvent.shiftKey);
+      aEvent.stopPropagation();
+    }
+    else if (cell.col.id == "restore")
+      toggleRowChecked(cell.row);
+  }
+}
+
+function onListKeyDown(aEvent) {
+  switch (aEvent.keyCode)
+  {
+  case KeyEvent.DOM_VK_SPACE:
+    toggleRowChecked(document.getElementById("tabList").currentIndex);
+    // Prevent page from scrolling on the space key.
+    aEvent.preventDefault();
+    break;
+  case KeyEvent.DOM_VK_RETURN:
+    var ix = document.getElementById("tabList").currentIndex;
+    if (aEvent.ctrlKey && !treeView.isContainer(ix))
+      restoreSingleTab(ix, aEvent.shiftKey);
+    break;
+  }
+}
+
+// Helper functions
+
+function getBrowserWindow() {
+  return window.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIWebNavigation)
+               .QueryInterface(Ci.nsIDocShellTreeItem).rootTreeItem
+               .QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindow);
+}
+
+function toggleRowChecked(aIx) {
+  function isChecked(aItem) {
+    return aItem.checked;
+  }
+
+  var item = gTreeData[aIx];
+  item.checked = !item.checked;
+  treeView.treeBox.invalidateRow(aIx);
+
+  if (treeView.isContainer(aIx)) {
+    // (un)check all tabs of this window as well
+    for (let tab of item.tabs) {
+      tab.checked = item.checked;
+      treeView.treeBox.invalidateRow(gTreeData.indexOf(tab));
+    }
+  }
+  else {
+    // update the window's checkmark as well (0 means "partially checked")
+    item.parent.checked = item.parent.tabs.every(isChecked) ? true :
+                          item.parent.tabs.some(isChecked) ? 0 : false;
+    treeView.treeBox.invalidateRow(gTreeData.indexOf(item.parent));
+  }
+
+  // we only disable the button when there's no cancel button.
+  if (document.getElementById("errorCancel")) {
+    document.getElementById("errorTryAgain").disabled = !gTreeData.some(isChecked);
+  }
+}
+
+function restoreSingleTab(aIx, aShifted) {
+  var tabbrowser = getBrowserWindow().gBrowser;
+  var newTab = tabbrowser.addTab();
+  var item = gTreeData[aIx];
+
+  var ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
+  var tabState = gStateObject.windows[item.parent.ix]
+                             .tabs[aIx - gTreeData.indexOf(item.parent) - 1];
+  // ensure tab would be visible on the tabstrip.
+  tabState.hidden = false;
+  ss.setTabState(newTab, JSON.stringify(tabState));
+
+  // respect the preference as to whether to select the tab (the Shift key inverses)
+  var prefBranch = Cc["@mozilla.org/preferences-service;1"].getService(Ci.nsIPrefBranch);
+  if (prefBranch.getBoolPref("browser.tabs.loadInBackground") != !aShifted)
+    tabbrowser.selectedTab = newTab;
+}
+
+// Tree controller
+
+var treeView = {
+  treeBox: null,
+  selection: null,
+
+  get rowCount()                     { return gTreeData.length; },
+  setTree: function(treeBox)         { this.treeBox = treeBox; },
+  getCellText: function(idx, column) { return gTreeData[idx].label; },
+  isContainer: function(idx)         { return "open" in gTreeData[idx]; },
+  getCellValue: function(idx, column){ return gTreeData[idx].checked; },
+  isContainerOpen: function(idx)     { return gTreeData[idx].open; },
+  isContainerEmpty: function(idx)    { return false; },
+  isSeparator: function(idx)         { return false; },
+  isSorted: function()               { return false; },
+  isEditable: function(idx, column)  { return false; },
+  canDrop: function(idx, orientation, dt) { return false; },
+  getLevel: function(idx)            { return this.isContainer(idx) ? 0 : 1; },
+
+  getParentIndex: function(idx) {
+    if (!this.isContainer(idx))
+      for (var t = idx - 1; t >= 0 ; t--)
+        if (this.isContainer(t))
+          return t;
+    return -1;
+  },
+
+  hasNextSibling: function(idx, after) {
+    var thisLevel = this.getLevel(idx);
+    for (var t = after + 1; t < gTreeData.length; t++)
+      if (this.getLevel(t) <= thisLevel)
+        return this.getLevel(t) == thisLevel;
+    return false;
+  },
+
+  toggleOpenState: function(idx) {
+    if (!this.isContainer(idx))
+      return;
+    var item = gTreeData[idx];
+    if (item.open) {
+      // remove this window's tab rows from the view
+      var thisLevel = this.getLevel(idx);
+      for (var t = idx + 1; t < gTreeData.length && this.getLevel(t) > thisLevel; t++);
+      var deletecount = t - idx - 1;
+      gTreeData.splice(idx + 1, deletecount);
+      this.treeBox.rowCountChanged(idx + 1, -deletecount);
+    }
+    else {
+      // add this window's tab rows to the view
+      var toinsert = gTreeData[idx].tabs;
+      for (var i = 0; i < toinsert.length; i++)
+        gTreeData.splice(idx + i + 1, 0, toinsert[i]);
+      this.treeBox.rowCountChanged(idx + 1, toinsert.length);
+    }
+    item.open = !item.open;
+    this.treeBox.invalidateRow(idx);
+  },
+
+  getCellProperties: function(idx, column) {
+    if (column.id == "restore" && this.isContainer(idx) && gTreeData[idx].checked === 0)
+      return "partial";
+    if (column.id == "title")
+      return this.getImageSrc(idx, column) ? "icon" : "noicon";
+
+    return "";
+  },
+
+  getRowProperties: function(idx) {
+    var winState = gTreeData[idx].parent || gTreeData[idx];
+    if (winState.ix % 2 != 0)
+      return "alternate";
+
+    return "";
+  },
+
+  getImageSrc: function(idx, column) {
+    if (column.id == "title")
+      return gTreeData[idx].src || null;
+    return null;
+  },
+
+  getProgressMode : function(idx, column) { },
+  cycleHeader: function(column) { },
+  cycleCell: function(idx, column) { },
+  selectionChanged: function() { },
+  performAction: function(action) { },
+  performActionOnCell: function(action, index, column) { },
+  getColumnProperties: function(column) { return ""; }
+};
diff --git a/browser/components/sessionstore/content/aboutSessionRestore.xhtml b/browser/components/sessionstore/content/aboutSessionRestore.xhtml
new file mode 100644
index 000000000..bcd9084e7
--- /dev/null
+++ b/browser/components/sessionstore/content/aboutSessionRestore.xhtml
@@ -0,0 +1,86 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+# 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 html [
+  <!ENTITY % htmlDTD PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "DTD/xhtml1-strict.dtd">
+  %htmlDTD;
+  <!ENTITY % netErrorDTD SYSTEM "chrome://global/locale/netError.dtd">
+  %netErrorDTD;
+  <!ENTITY % globalDTD SYSTEM "chrome://global/locale/global.dtd">
+  %globalDTD;
+  <!ENTITY % restorepageDTD SYSTEM "chrome://browser/locale/aboutSessionRestore.dtd">
+  %restorepageDTD;
+]>
+
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+  <head>
+    <title>&restorepage.tabtitle;</title>
+    <link rel="stylesheet" href="chrome://global/skin/in-content/info-pages.css" type="text/css" media="all"/>
+    <link rel="stylesheet" href="chrome://browser/skin/aboutSessionRestore.css" type="text/css" media="all"/>
+    <link rel="icon" type="image/png" href="chrome://global/skin/icons/warning-16.png"/>
+
+    <script type="application/javascript;version=1.8" src="chrome://browser/content/aboutSessionRestore.js"/>
+  </head>
+
+  <body dir="&locale.dir;">
+
+    <div class="container restore-chosen">
+
+      <div class="title">
+        <h1 class="title-text">&restorepage.errorTitle;</h1>
+      </div>
+      <div class="description">
+        <p>&restorepage.problemDesc;</p>
+
+        <div id="errorLongDesc">
+          <p>&restorepage.tryThis;</p>
+          <ul>
+            <li>&restorepage.restoreSome;</li>
+            <li>&restorepage.startNew;</li>
+          </ul>
+        </div>
+      </div>
+      <div class="tree-container" available="true">
+        <xul:tree id="tabList" seltype="single" hidecolumnpicker="true"
+              onclick="onListClick(event);" onkeydown="onListKeyDown(event);"
+              _window_label="&restorepage.windowLabel;">
+          <xul:treecols>
+            <xul:treecol cycler="true" id="restore" type="checkbox" label="&restorepage.restoreHeader;"/>
+            <xul:splitter class="tree-splitter"/>
+            <xul:treecol primary="true" id="title" label="&restorepage.listHeader;" flex="1"/>
+          </xul:treecols>
+          <xul:treechildren flex="1"/>
+        </xul:tree>
+      </div>
+      <div class="button-container">
+#ifdef XP_UNIX
+        <xul:button id="errorCancel"
+                label="&restorepage.closeButton;"
+                accesskey="&restorepage.close.access;"
+                oncommand="startNewSession();"/>
+        <xul:button class="primary"
+                id="errorTryAgain"
+                label="&restorepage.tryagainButton;"
+                accesskey="&restorepage.restore.access;"
+                oncommand="restoreSession();"/>
+#else
+        <xul:button class="primary"
+                id="errorTryAgain"
+                label="&restorepage.tryagainButton;"
+                accesskey="&restorepage.restore.access;"
+                oncommand="restoreSession();"/>
+        <xul:button id="errorCancel"
+                label="&restorepage.closeButton;"
+                accesskey="&restorepage.close.access;"
+                oncommand="startNewSession();"/>
+#endif
+      </div>
+      <!-- holds the session data for when the tab is closed -->
+      <input type="text" id="sessionData" style="display: none;"/>
+    </div>
+
+  </body>
+</html>
diff --git a/browser/components/sessionstore/content/content-sessionStore.js b/browser/components/sessionstore/content/content-sessionStore.js
new file mode 100644
index 000000000..858e35750
--- /dev/null
+++ b/browser/components/sessionstore/content/content-sessionStore.js
@@ -0,0 +1,897 @@
+/* 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/. */
+
+"use strict";
+
+function debug(msg) {
+  Services.console.logStringMessage("SessionStoreContent: " + msg);
+}
+
+var Cu = Components.utils;
+var Cc = Components.classes;
+var Ci = Components.interfaces;
+var Cr = Components.results;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
+Cu.import("resource://gre/modules/Timer.jsm", this);
+
+XPCOMUtils.defineLazyModuleGetter(this, "FormData",
+  "resource://gre/modules/FormData.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "Preferences",
+  "resource://gre/modules/Preferences.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "DocShellCapabilities",
+  "resource:///modules/sessionstore/DocShellCapabilities.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "PageStyle",
+  "resource:///modules/sessionstore/PageStyle.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "ScrollPosition",
+  "resource://gre/modules/ScrollPosition.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "SessionHistory",
+  "resource:///modules/sessionstore/SessionHistory.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "SessionStorage",
+  "resource:///modules/sessionstore/SessionStorage.jsm");
+
+Cu.import("resource:///modules/sessionstore/FrameTree.jsm", this);
+var gFrameTree = new FrameTree(this);
+
+Cu.import("resource:///modules/sessionstore/ContentRestore.jsm", this);
+XPCOMUtils.defineLazyGetter(this, 'gContentRestore',
+                            () => { return new ContentRestore(this) });
+
+// The current epoch.
+var gCurrentEpoch = 0;
+
+// A bound to the size of data to store for DOM Storage.
+const DOM_STORAGE_MAX_CHARS = 10000000; // 10M characters
+
+// This pref controls whether or not we send updates to the parent on a timeout
+// or not, and should only be used for tests or debugging.
+const TIMEOUT_DISABLED_PREF = "browser.sessionstore.debug.no_auto_updates";
+
+const kNoIndex = Number.MAX_SAFE_INTEGER;
+const kLastIndex = Number.MAX_SAFE_INTEGER - 1;
+
+/**
+ * Returns a lazy function that will evaluate the given
+ * function |fn| only once and cache its return value.
+ */
+function createLazy(fn) {
+  let cached = false;
+  let cachedValue = null;
+
+  return function lazy() {
+    if (!cached) {
+      cachedValue = fn();
+      cached = true;
+    }
+
+    return cachedValue;
+  };
+}
+
+/**
+ * Listens for and handles content events that we need for the
+ * session store service to be notified of state changes in content.
+ */
+var EventListener = {
+
+  init: function () {
+    addEventListener("load", this, true);
+  },
+
+  handleEvent: function (event) {
+    // Ignore load events from subframes.
+    if (event.target != content.document) {
+      return;
+    }
+
+    if (content.document.documentURI.startsWith("about:reader")) {
+      if (event.type == "load" &&
+          !content.document.body.classList.contains("loaded")) {
+        // Don't restore the scroll position of an about:reader page at this
+        // point; listen for the custom event dispatched from AboutReader.jsm.
+        content.addEventListener("AboutReaderContentReady", this);
+        return;
+      }
+
+      content.removeEventListener("AboutReaderContentReady", this);
+    }
+
+    // Restore the form data and scroll position. If we're not currently
+    // restoring a tab state then this call will simply be a noop.
+    gContentRestore.restoreDocument();
+  }
+};
+
+/**
+ * Listens for and handles messages sent by the session store service.
+ */
+var MessageListener = {
+
+  MESSAGES: [
+    "SessionStore:restoreHistory",
+    "SessionStore:restoreTabContent",
+    "SessionStore:resetRestore",
+    "SessionStore:flush",
+  ],
+
+  init: function () {
+    this.MESSAGES.forEach(m => addMessageListener(m, this));
+  },
+
+  receiveMessage: function ({name, data}) {
+    // The docShell might be gone. Don't process messages,
+    // that will just lead to errors anyway.
+    if (!docShell) {
+      return;
+    }
+
+    // A fresh tab always starts with epoch=0. The parent has the ability to
+    // override that to signal a new era in this tab's life. This enables it
+    // to ignore async messages that were already sent but not yet received
+    // and would otherwise confuse the internal tab state.
+    if (data.epoch && data.epoch != gCurrentEpoch) {
+      gCurrentEpoch = data.epoch;
+    }
+
+    switch (name) {
+      case "SessionStore:restoreHistory":
+        this.restoreHistory(data);
+        break;
+      case "SessionStore:restoreTabContent":
+        this.restoreTabContent(data);
+        break;
+      case "SessionStore:resetRestore":
+        gContentRestore.resetRestore();
+        break;
+      case "SessionStore:flush":
+        this.flush(data);
+        break;
+      default:
+        debug("received unknown message '" + name + "'");
+        break;
+    }
+  },
+
+  restoreHistory({epoch, tabData, loadArguments, isRemotenessUpdate}) {
+    gContentRestore.restoreHistory(tabData, loadArguments, {
+      // Note: The callbacks passed here will only be used when a load starts
+      // that was not initiated by sessionstore itself. This can happen when
+      // some code calls browser.loadURI() or browser.reload() on a pending
+      // browser/tab.
+
+      onLoadStarted() {
+        // Notify the parent that the tab is no longer pending.
+        sendSyncMessage("SessionStore:restoreTabContentStarted", {epoch});
+      },
+
+      onLoadFinished() {
+        // Tell SessionStore.jsm that it may want to restore some more tabs,
+        // since it restores a max of MAX_CONCURRENT_TAB_RESTORES at a time.
+        sendAsyncMessage("SessionStore:restoreTabContentComplete", {epoch});
+      }
+    });
+
+    // When restoreHistory finishes, we send a synchronous message to
+    // SessionStore.jsm so that it can run SSTabRestoring. Users of
+    // SSTabRestoring seem to get confused if chrome and content are out of
+    // sync about the state of the restore (particularly regarding
+    // docShell.currentURI). Using a synchronous message is the easiest way
+    // to temporarily synchronize them.
+    sendSyncMessage("SessionStore:restoreHistoryComplete", {epoch, isRemotenessUpdate});
+  },
+
+  restoreTabContent({loadArguments, isRemotenessUpdate}) {
+    let epoch = gCurrentEpoch;
+
+    // We need to pass the value of didStartLoad back to SessionStore.jsm.
+    let didStartLoad = gContentRestore.restoreTabContent(loadArguments, isRemotenessUpdate, () => {
+      // Tell SessionStore.jsm that it may want to restore some more tabs,
+      // since it restores a max of MAX_CONCURRENT_TAB_RESTORES at a time.
+      sendAsyncMessage("SessionStore:restoreTabContentComplete", {epoch, isRemotenessUpdate});
+    });
+
+    sendAsyncMessage("SessionStore:restoreTabContentStarted", {epoch, isRemotenessUpdate});
+
+    if (!didStartLoad) {
+      // Pretend that the load succeeded so that event handlers fire correctly.
+      sendAsyncMessage("SessionStore:restoreTabContentComplete", {epoch, isRemotenessUpdate});
+    }
+  },
+
+  flush({id}) {
+    // Flush the message queue, send the latest updates.
+    MessageQueue.send({flushID: id});
+  }
+};
+
+/**
+ * Listens for changes to the session history. Whenever the user navigates
+ * we will collect URLs and everything belonging to session history.
+ *
+ * Causes a SessionStore:update message to be sent that contains the current
+ * session history.
+ *
+ * Example:
+ *   {entries: [{url: "about:mozilla", ...}, ...], index: 1}
+ */
+var SessionHistoryListener = {
+  init: function () {
+    // The frame tree observer is needed to handle initial subframe loads.
+    // It will redundantly invalidate with the SHistoryListener in some cases
+    // but these invalidations are very cheap.
+    gFrameTree.addObserver(this);
+
+    // By adding the SHistoryListener immediately, we will unfortunately be
+    // notified of every history entry as the tab is restored. We don't bother
+    // waiting to add the listener later because these notifications are cheap.
+    // We will likely only collect once since we are batching collection on
+    // a delay.
+    docShell.QueryInterface(Ci.nsIWebNavigation).sessionHistory.
+      addSHistoryListener(this);
+
+    // Collect data if we start with a non-empty shistory.
+    if (!SessionHistory.isEmpty(docShell)) {
+      this.collect();
+      // When a tab is detached from the window, for the new window there is a
+      // new SessionHistoryListener created. Normally it is empty at this point
+      // but in a test env. the initial about:blank might have a children in which
+      // case we fire off a history message here with about:blank in it. If we
+      // don't do it ASAP then there is going to be a browser swap and the parent
+      // will be all confused by that message.
+      MessageQueue.send();
+    }
+
+    // Listen for page title changes.
+    addEventListener("DOMTitleChanged", this);
+  },
+
+  uninit: function () {
+    let sessionHistory = docShell.QueryInterface(Ci.nsIWebNavigation).sessionHistory;
+    if (sessionHistory) {
+      sessionHistory.removeSHistoryListener(this);
+    }
+  },
+
+  collect: function () {
+    this._fromIdx = kNoIndex;
+    if (docShell) {
+      MessageQueue.push("history", () => SessionHistory.collect(docShell));
+    }
+  },
+
+  _fromIdx: kNoIndex,
+
+  // History can grow relatively big with the nested elements, so if we don't have to, we
+  // don't want to send the entire history all the time. For a simple optimization
+  // we keep track of the smallest index from after any change has occured and we just send
+  // the elements from that index. If something more complicated happens we just clear it
+  // and send the entire history. We always send the additional info like the current selected
+  // index (so for going back and forth between history entries we set the index to kLastIndex
+  // if nothing else changed send an empty array and the additonal info like the selected index)
+  collectFrom: function (idx) {
+    if (this._fromIdx <= idx) {
+      // If we already know that we need to update history fromn index N we can ignore any changes
+      // tha happened with an element with index larger than N.
+      // Note: initially we use kNoIndex which is MAX_SAFE_INTEGER which means we don't ignore anything
+      // here, and in case of navigation in the history back and forth we use kLastIndex which ignores
+      // only the subsequent navigations, but not any new elements added.
+      return;
+    }
+
+    this._fromIdx = idx;
+    MessageQueue.push("historychange", () => {
+      if (this._fromIdx === kNoIndex) {
+        return null;
+      }
+
+      let history = SessionHistory.collect(docShell);
+      if (kLastIndex == idx) {
+        history.entries = [];
+      } else {
+        history.entries.splice(0, this._fromIdx + 1);
+      }
+
+      history.fromIdx = this._fromIdx;
+
+      this._fromIdx = kNoIndex;
+      return history;
+    });
+  },
+
+  handleEvent(event) {
+    this.collect();
+  },
+
+  onFrameTreeCollected: function () {
+    this.collect();
+  },
+
+  onFrameTreeReset: function () {
+    this.collect();
+  },
+
+  OnHistoryNewEntry: function (newURI, oldIndex) {
+    this.collectFrom(oldIndex);
+  },
+
+  OnHistoryGoBack: function (backURI) {
+    this.collectFrom(kLastIndex);
+    return true;
+  },
+
+  OnHistoryGoForward: function (forwardURI) {
+    this.collectFrom(kLastIndex);
+    return true;
+  },
+
+  OnHistoryGotoIndex: function (index, gotoURI) {
+    this.collectFrom(kLastIndex);
+    return true;
+  },
+
+  OnHistoryPurge: function (numEntries) {
+    this.collect();
+    return true;
+  },
+
+  OnHistoryReload: function (reloadURI, reloadFlags) {
+    this.collect();
+    return true;
+  },
+
+  OnHistoryReplaceEntry: function (index) {
+    this.collect();
+  },
+
+  QueryInterface: XPCOMUtils.generateQI([
+    Ci.nsISHistoryListener,
+    Ci.nsISupportsWeakReference
+  ])
+};
+
+/**
+ * Listens for scroll position changes. Whenever the user scrolls the top-most
+ * frame we update the scroll position and will restore it when requested.
+ *
+ * Causes a SessionStore:update message to be sent that contains the current
+ * scroll positions as a tree of strings. If no frame of the whole frame tree
+ * is scrolled this will return null so that we don't tack a property onto
+ * the tabData object in the parent process.
+ *
+ * Example:
+ *   {scroll: "100,100", children: [null, null, {scroll: "200,200"}]}
+ */
+var ScrollPositionListener = {
+  init: function () {
+    addEventListener("scroll", this);
+    gFrameTree.addObserver(this);
+  },
+
+  handleEvent: function (event) {
+    let frame = event.target.defaultView;
+
+    // Don't collect scroll data for frames created at or after the load event
+    // as SessionStore can't restore scroll data for those.
+    if (gFrameTree.contains(frame)) {
+      MessageQueue.push("scroll", () => this.collect());
+    }
+  },
+
+  onFrameTreeCollected: function () {
+    MessageQueue.push("scroll", () => this.collect());
+  },
+
+  onFrameTreeReset: function () {
+    MessageQueue.push("scroll", () => null);
+  },
+
+  collect: function () {
+    return gFrameTree.map(ScrollPosition.collect);
+  }
+};
+
+/**
+ * Listens for changes to input elements. Whenever the value of an input
+ * element changes we will re-collect data for the current frame tree and send
+ * a message to the parent process.
+ *
+ * Causes a SessionStore:update message to be sent that contains the form data
+ * for all reachable frames.
+ *
+ * Example:
+ *   {
+ *     formdata: {url: "http://mozilla.org/", id: {input_id: "input value"}},
+ *     children: [
+ *       null,
+ *       {url: "http://sub.mozilla.org/", id: {input_id: "input value 2"}}
+ *     ]
+ *   }
+ */
+var FormDataListener = {
+  init: function () {
+    addEventListener("input", this, true);
+    addEventListener("change", this, true);
+    gFrameTree.addObserver(this);
+  },
+
+  handleEvent: function (event) {
+    let frame = event.target.ownerGlobal;
+
+    // Don't collect form data for frames created at or after the load event
+    // as SessionStore can't restore form data for those.
+    if (gFrameTree.contains(frame)) {
+      MessageQueue.push("formdata", () => this.collect());
+    }
+  },
+
+  onFrameTreeReset: function () {
+    MessageQueue.push("formdata", () => null);
+  },
+
+  collect: function () {
+    return gFrameTree.map(FormData.collect);
+  }
+};
+
+/**
+ * Listens for changes to the page style. Whenever a different page style is
+ * selected or author styles are enabled/disabled we send a message with the
+ * currently applied style to the chrome process.
+ *
+ * Causes a SessionStore:update message to be sent that contains the currently
+ * selected pageStyle for all reachable frames.
+ *
+ * Example:
+ *   {pageStyle: "Dusk", children: [null, {pageStyle: "Mozilla"}]}
+ */
+var PageStyleListener = {
+  init: function () {
+    Services.obs.addObserver(this, "author-style-disabled-changed", false);
+    Services.obs.addObserver(this, "style-sheet-applicable-state-changed", false);
+    gFrameTree.addObserver(this);
+  },
+
+  uninit: function () {
+    Services.obs.removeObserver(this, "author-style-disabled-changed");
+    Services.obs.removeObserver(this, "style-sheet-applicable-state-changed");
+  },
+
+  observe: function (subject, topic) {
+    let frame = subject.defaultView;
+
+    if (frame && gFrameTree.contains(frame)) {
+      MessageQueue.push("pageStyle", () => this.collect());
+    }
+  },
+
+  collect: function () {
+    return PageStyle.collect(docShell, gFrameTree);
+  },
+
+  onFrameTreeCollected: function () {
+    MessageQueue.push("pageStyle", () => this.collect());
+  },
+
+  onFrameTreeReset: function () {
+    MessageQueue.push("pageStyle", () => null);
+  }
+};
+
+/**
+ * Listens for changes to docShell capabilities. Whenever a new load is started
+ * we need to re-check the list of capabilities and send message when it has
+ * changed.
+ *
+ * Causes a SessionStore:update message to be sent that contains the currently
+ * disabled docShell capabilities (all nsIDocShell.allow* properties set to
+ * false) as a string - i.e. capability names separate by commas.
+ */
+var DocShellCapabilitiesListener = {
+  /**
+   * This field is used to compare the last docShell capabilities to the ones
+   * that have just been collected. If nothing changed we won't send a message.
+   */
+  _latestCapabilities: "",
+
+  init: function () {
+    gFrameTree.addObserver(this);
+  },
+
+  /**
+   * onFrameTreeReset() is called as soon as we start loading a page.
+   */
+  onFrameTreeReset: function() {
+    // The order of docShell capabilities cannot change while we're running
+    // so calling join() without sorting before is totally sufficient.
+    let caps = DocShellCapabilities.collect(docShell).join(",");
+
+    // Send new data only when the capability list changes.
+    if (caps != this._latestCapabilities) {
+      this._latestCapabilities = caps;
+      MessageQueue.push("disallow", () => caps || null);
+    }
+  }
+};
+
+/**
+ * Listens for changes to the DOMSessionStorage. Whenever new keys are added,
+ * existing ones removed or changed, or the storage is cleared we will send a
+ * message to the parent process containing up-to-date sessionStorage data.
+ *
+ * Causes a SessionStore:update message to be sent that contains the current
+ * DOMSessionStorage contents. The data is a nested object using host names
+ * as keys and per-host DOMSessionStorage data as values.
+ */
+var SessionStorageListener = {
+  init: function () {
+    addEventListener("MozSessionStorageChanged", this, true);
+    Services.obs.addObserver(this, "browser:purge-domain-data", false);
+    gFrameTree.addObserver(this);
+  },
+
+  uninit: function () {
+    Services.obs.removeObserver(this, "browser:purge-domain-data");
+  },
+
+  handleEvent: function (event) {
+    if (gFrameTree.contains(event.target)) {
+      this.collectFromEvent(event);
+    }
+  },
+
+  observe: function () {
+    // Collect data on the next tick so that any other observer
+    // that needs to purge data can do its work first.
+    setTimeout(() => this.collect(), 0);
+  },
+
+  // Before DOM Storage can be written to disk, it needs to be serialized
+  // for sending across frames/processes, then again to be sent across
+  // threads, then again to be put in a buffer for the disk. Each of these
+  // serializations is an opportunity to OOM and (depending on the site of
+  // the OOM), either crash, lose all data for the frame or lose all data
+  // for the application.
+  //
+  // In order to avoid this, compute an estimate of the size of the
+  // object, and block SessionStorage items that are too large. As
+  // we also don't want to cause an OOM here, we use a quick and memory-
+  // efficient approximation: we compute the total sum of string lengths
+  // involved in this object.
+  estimateStorageSize: function(collected) {
+    if (!collected) {
+      return 0;
+    }
+
+    let size = 0;
+    for (let host of Object.keys(collected)) {
+      size += host.length;
+      let perHost = collected[host];
+      for (let key of Object.keys(perHost)) {
+        size += key.length;
+        let perKey = perHost[key];
+        size += perKey.length;
+      }
+    }
+
+    return size;
+  },
+
+  // We don't want to send all the session storage data for all the frames
+  // for every change. So if only a few value changed we send them over as
+  // a "storagechange" event. If however for some reason before we send these
+  // changes we have to send over the entire sessions storage data, we just
+  // reset these changes.
+  _changes: undefined,
+
+  resetChanges: function () {
+    this._changes = undefined;
+  },
+
+  collectFromEvent: function (event) {
+    // TODO: we should take browser.sessionstore.dom_storage_limit into an account here.
+    if (docShell) {
+      let {url, key, newValue} = event;
+      let uri = Services.io.newURI(url, null, null);
+      let domain = uri.prePath;
+      if (!this._changes) {
+        this._changes = {};
+      }
+      if (!this._changes[domain]) {
+        this._changes[domain] = {};
+      }
+      this._changes[domain][key] = newValue;
+
+      MessageQueue.push("storagechange", () => {
+        let tmp = this._changes;
+        // If there were multiple changes we send them merged.
+        // First one will collect all the changes the rest of
+        // these messages will be ignored.
+        this.resetChanges();
+        return tmp;
+      });
+    }
+  },
+
+  collect: function () {
+    if (docShell) {
+      // We need the entire session storage, let's reset the pending individual change
+      // messages.
+      this.resetChanges();
+      MessageQueue.push("storage", () => {
+        let collected = SessionStorage.collect(docShell, gFrameTree);
+
+        if (collected == null) {
+          return collected;
+        }
+
+        let size = this.estimateStorageSize(collected);
+
+        MessageQueue.push("telemetry", () => ({ FX_SESSION_RESTORE_DOM_STORAGE_SIZE_ESTIMATE_CHARS: size }));
+        if (size > Preferences.get("browser.sessionstore.dom_storage_limit", DOM_STORAGE_MAX_CHARS)) {
+          // Rather than keeping the old storage, which wouldn't match the rest
+          // of the state of the page, empty the storage. DOM storage will be
+          // recollected the next time and stored if it is now small enough.
+          return {};
+        }
+
+        return collected;
+      });
+    }
+  },
+
+  onFrameTreeCollected: function () {
+    this.collect();
+  },
+
+  onFrameTreeReset: function () {
+    this.collect();
+  }
+};
+
+/**
+ * Listen for changes to the privacy status of the tab.
+ * By definition, tabs start in non-private mode.
+ *
+ * Causes a SessionStore:update message to be sent for
+ * field "isPrivate". This message contains
+ *  |true| if the tab is now private
+ *  |null| if the tab is now public - the field is therefore
+ *  not saved.
+ */
+var PrivacyListener = {
+  init: function() {
+    docShell.addWeakPrivacyTransitionObserver(this);
+
+    // Check that value at startup as it might have
+    // been set before the frame script was loaded.
+    if (docShell.QueryInterface(Ci.nsILoadContext).usePrivateBrowsing) {
+      MessageQueue.push("isPrivate", () => true);
+    }
+  },
+
+  // Ci.nsIPrivacyTransitionObserver
+  privateModeChanged: function(enabled) {
+    MessageQueue.push("isPrivate", () => enabled || null);
+  },
+
+  QueryInterface: XPCOMUtils.generateQI([Ci.nsIPrivacyTransitionObserver,
+                                         Ci.nsISupportsWeakReference])
+};
+
+/**
+ * A message queue that takes collected data and will take care of sending it
+ * to the chrome process. It allows flushing using synchronous messages and
+ * takes care of any race conditions that might occur because of that. Changes
+ * will be batched if they're pushed in quick succession to avoid a message
+ * flood.
+ */
+var MessageQueue = {
+  /**
+   * A map (string -> lazy fn) holding lazy closures of all queued data
+   * collection routines. These functions will return data collected from the
+   * docShell.
+   */
+  _data: new Map(),
+
+  /**
+   * The delay (in ms) used to delay sending changes after data has been
+   * invalidated.
+   */
+  BATCH_DELAY_MS: 1000,
+
+  /**
+   * The current timeout ID, null if there is no queue data. We use timeouts
+   * to damp a flood of data changes and send lots of changes as one batch.
+   */
+  _timeout: null,
+
+  /**
+   * Whether or not sending batched messages on a timer is disabled. This should
+   * only be used for debugging or testing. If you need to access this value,
+   * you should probably use the timeoutDisabled getter.
+   */
+  _timeoutDisabled: false,
+
+  /**
+   * True if batched messages are not being fired on a timer. This should only
+   * ever be true when debugging or during tests.
+   */
+  get timeoutDisabled() {
+    return this._timeoutDisabled;
+  },
+
+  /**
+   * Disables sending batched messages on a timer. Also cancels any pending
+   * timers.
+   */
+  set timeoutDisabled(val) {
+    this._timeoutDisabled = val;
+
+    if (val && this._timeout) {
+      clearTimeout(this._timeout);
+      this._timeout = null;
+    }
+
+    return val;
+  },
+
+  init() {
+    this.timeoutDisabled =
+      Services.prefs.getBoolPref(TIMEOUT_DISABLED_PREF);
+
+    Services.prefs.addObserver(TIMEOUT_DISABLED_PREF, this, false);
+  },
+
+  uninit() {
+    Services.prefs.removeObserver(TIMEOUT_DISABLED_PREF, this);
+  },
+
+  observe(subject, topic, data) {
+    if (topic == "nsPref:changed" && data == TIMEOUT_DISABLED_PREF) {
+      this.timeoutDisabled =
+        Services.prefs.getBoolPref(TIMEOUT_DISABLED_PREF);
+    }
+  },
+
+  /**
+   * Pushes a given |value| onto the queue. The given |key| represents the type
+   * of data that is stored and can override data that has been queued before
+   * but has not been sent to the parent process, yet.
+   *
+   * @param key (string)
+   *        A unique identifier specific to the type of data this is passed.
+   * @param fn (function)
+   *        A function that returns the value that will be sent to the parent
+   *        process.
+   */
+  push: function (key, fn) {
+    this._data.set(key, createLazy(fn));
+
+    if (!this._timeout && !this._timeoutDisabled) {
+      // Wait a little before sending the message to batch multiple changes.
+      this._timeout = setTimeout(() => this.send(), this.BATCH_DELAY_MS);
+    }
+  },
+
+  /**
+   * Sends queued data to the chrome process.
+   *
+   * @param options (object)
+   *        {flushID: 123} to specify that this is a flush
+   *        {isFinal: true} to signal this is the final message sent on unload
+   */
+  send: function (options = {}) {
+    // Looks like we have been called off a timeout after the tab has been
+    // closed. The docShell is gone now and we can just return here as there
+    // is nothing to do.
+    if (!docShell) {
+      return;
+    }
+
+    if (this._timeout) {
+      clearTimeout(this._timeout);
+      this._timeout = null;
+    }
+
+    let flushID = (options && options.flushID) || 0;
+
+    let durationMs = Date.now();
+
+    let data = {};
+    let telemetry = {};
+    for (let [key, func] of this._data) {
+      let value = func();
+      if (key == "telemetry") {
+        for (let histogramId of Object.keys(value)) {
+          telemetry[histogramId] = value[histogramId];
+        }
+      } else if (value || (key != "storagechange" && key != "historychange")) {
+        data[key] = value;
+      }
+    }
+
+    this._data.clear();
+
+    durationMs = Date.now() - durationMs;
+    telemetry.FX_SESSION_RESTORE_CONTENT_COLLECT_DATA_LONGEST_OP_MS = durationMs;
+
+    try {
+      // Send all data to the parent process.
+      sendAsyncMessage("SessionStore:update", {
+        data, telemetry, flushID,
+        isFinal: options.isFinal || false,
+        epoch: gCurrentEpoch
+      });
+    } catch (ex if ex && ex.result == Cr.NS_ERROR_OUT_OF_MEMORY) {
+      let telemetry = {
+        FX_SESSION_RESTORE_SEND_UPDATE_CAUSED_OOM: 1
+      };
+      sendAsyncMessage("SessionStore:error", {
+        telemetry
+      });
+    }
+  },
+};
+
+EventListener.init();
+MessageListener.init();
+FormDataListener.init();
+PageStyleListener.init();
+SessionHistoryListener.init();
+SessionStorageListener.init();
+ScrollPositionListener.init();
+DocShellCapabilitiesListener.init();
+PrivacyListener.init();
+MessageQueue.init();
+
+function handleRevivedTab() {
+  if (!content) {
+    removeEventListener("pagehide", handleRevivedTab);
+    return;
+  }
+
+  if (content.document.documentURI.startsWith("about:tabcrashed")) {
+    if (Services.appinfo.processType != Services.appinfo.PROCESS_TYPE_DEFAULT) {
+      // Sanity check - we'd better be loading this in a non-remote browser.
+      throw new Error("We seem to be navigating away from about:tabcrashed in " +
+                      "a non-remote browser. This should really never happen.");
+    }
+
+    removeEventListener("pagehide", handleRevivedTab);
+
+    // Notify the parent.
+    sendAsyncMessage("SessionStore:crashedTabRevived");
+  }
+}
+
+// If we're browsing from the tab crashed UI to a blacklisted URI that keeps
+// this browser non-remote, we'll handle that in a pagehide event.
+addEventListener("pagehide", handleRevivedTab);
+
+addEventListener("unload", () => {
+  // Upon frameLoader destruction, send a final update message to
+  // the parent and flush all data currently held in the child.
+  MessageQueue.send({isFinal: true});
+
+  // If we're browsing from the tab crashed UI to a URI that causes the tab
+  // to go remote again, we catch this in the unload event handler, because
+  // swapping out the non-remote browser for a remote one in
+  // tabbrowser.xml's updateBrowserRemoteness doesn't cause the pagehide
+  // event to be fired.
+  handleRevivedTab();
+
+  // Remove all registered nsIObservers.
+  PageStyleListener.uninit();
+  SessionStorageListener.uninit();
+  SessionHistoryListener.uninit();
+  MessageQueue.uninit();
+
+  // Remove progress listeners.
+  gContentRestore.resetRestore();
+
+  // We don't need to take care of any gFrameTree observers as the gFrameTree
+  // will die with the content script. The same goes for the privacy transition
+  // observer that will die with the docShell when the tab is closed.
+});