Add m-esr52 at 52.6.0

10 files changed, 1950 insertions, 0 deletions

diff --git a/devtools/client/inspector/markup/views/element-container.js b/devtools/client/inspector/markup/views/element-container.js
new file mode 100644
index 000000000..851a803cb
--- /dev/null
+++ b/devtools/client/inspector/markup/views/element-container.js
@@ -0,0 +1,193 @@
+/* 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";
+
+const PREVIEW_MAX_DIM_PREF = "devtools.inspector.imagePreviewTooltipSize";
+
+const promise = require("promise");
+const Services = require("Services");
+const Heritage = require("sdk/core/heritage");
+const {Task} = require("devtools/shared/task");
+const nodeConstants = require("devtools/shared/dom-node-constants");
+const clipboardHelper = require("devtools/shared/platform/clipboard");
+const {setImageTooltip, setBrokenImageTooltip} =
+      require("devtools/client/shared/widgets/tooltip/ImageTooltipHelper");
+const {setEventTooltip} = require("devtools/client/shared/widgets/tooltip/EventTooltipHelper");
+const MarkupContainer = require("devtools/client/inspector/markup/views/markup-container");
+const ElementEditor = require("devtools/client/inspector/markup/views/element-editor");
+
+/**
+ * An implementation of MarkupContainer for Elements that can contain
+ * child nodes.
+ * Allows editing of tag name, attributes, expanding / collapsing.
+ *
+ * @param  {MarkupView} markupView
+ *         The markup view that owns this container.
+ * @param  {NodeFront} node
+ *         The node to display.
+ */
+function MarkupElementContainer(markupView, node) {
+  MarkupContainer.prototype.initialize.call(this, markupView, node,
+    "elementcontainer");
+
+  if (node.nodeType === nodeConstants.ELEMENT_NODE) {
+    this.editor = new ElementEditor(this, node);
+  } else {
+    throw new Error("Invalid node for MarkupElementContainer");
+  }
+
+  this.tagLine.appendChild(this.editor.elt);
+}
+
+MarkupElementContainer.prototype = Heritage.extend(MarkupContainer.prototype, {
+  _buildEventTooltipContent: Task.async(function* (target, tooltip) {
+    if (target.hasAttribute("data-event")) {
+      yield tooltip.hide();
+
+      let listenerInfo = yield this.node.getEventListenerInfo();
+
+      let toolbox = this.markup.toolbox;
+      setEventTooltip(tooltip, listenerInfo, toolbox);
+      // Disable the image preview tooltip while we display the event details
+      this.markup._disableImagePreviewTooltip();
+      tooltip.once("hidden", () => {
+        // Enable the image preview tooltip after closing the event details
+        this.markup._enableImagePreviewTooltip();
+      });
+      tooltip.show(target);
+    }
+  }),
+
+  /**
+   * Generates the an image preview for this Element. The element must be an
+   * image or canvas (@see isPreviewable).
+   *
+   * @return {Promise} that is resolved with an object of form
+   *         { data, size: { naturalWidth, naturalHeight, resizeRatio } } where
+   *         - data is the data-uri for the image preview.
+   *         - size contains information about the original image size and if
+   *         the preview has been resized.
+   *
+   * If this element is not previewable or the preview cannot be generated for
+   * some reason, the Promise is rejected.
+   */
+  _getPreview: function () {
+    if (!this.isPreviewable()) {
+      return promise.reject("_getPreview called on a non-previewable element.");
+    }
+
+    if (this.tooltipDataPromise) {
+      // A preview request is already pending. Re-use that request.
+      return this.tooltipDataPromise;
+    }
+
+    // Fetch the preview from the server.
+    this.tooltipDataPromise = Task.spawn(function* () {
+      let maxDim = Services.prefs.getIntPref(PREVIEW_MAX_DIM_PREF);
+      let preview = yield this.node.getImageData(maxDim);
+      let data = yield preview.data.string();
+
+      // Clear the pending preview request. We can't reuse the results later as
+      // the preview contents might have changed.
+      this.tooltipDataPromise = null;
+      return { data, size: preview.size };
+    }.bind(this));
+
+    return this.tooltipDataPromise;
+  },
+
+  /**
+   * Executed by MarkupView._isImagePreviewTarget which is itself called when
+   * the mouse hovers over a target in the markup-view.
+   * Checks if the target is indeed something we want to have an image tooltip
+   * preview over and, if so, inserts content into the tooltip.
+   *
+   * @return {Promise} that resolves when the tooltip content is ready. Resolves
+   * true if the tooltip should be displayed, false otherwise.
+   */
+  isImagePreviewTarget: Task.async(function* (target, tooltip) {
+    // Is this Element previewable.
+    if (!this.isPreviewable()) {
+      return false;
+    }
+
+    // If the Element has an src attribute, the tooltip is shown when hovering
+    // over the src url. If not, the tooltip is shown when hovering over the tag
+    // name.
+    let src = this.editor.getAttributeElement("src");
+    let expectedTarget = src ? src.querySelector(".link") : this.editor.tag;
+    if (target !== expectedTarget) {
+      return false;
+    }
+
+    try {
+      let { data, size } = yield this._getPreview();
+      // The preview is ready.
+      let options = {
+        naturalWidth: size.naturalWidth,
+        naturalHeight: size.naturalHeight,
+        maxDim: Services.prefs.getIntPref(PREVIEW_MAX_DIM_PREF)
+      };
+
+      setImageTooltip(tooltip, this.markup.doc, data, options);
+    } catch (e) {
+      // Indicate the failure but show the tooltip anyway.
+      setBrokenImageTooltip(tooltip, this.markup.doc);
+    }
+    return true;
+  }),
+
+  copyImageDataUri: function () {
+    // We need to send again a request to gettooltipData even if one was sent
+    // for the tooltip, because we want the full-size image
+    this.node.getImageData().then(data => {
+      data.data.string().then(str => {
+        clipboardHelper.copyString(str);
+      });
+    });
+  },
+
+  setInlineTextChild: function (inlineTextChild) {
+    this.inlineTextChild = inlineTextChild;
+    this.editor.updateTextEditor();
+  },
+
+  clearInlineTextChild: function () {
+    this.inlineTextChild = undefined;
+    this.editor.updateTextEditor();
+  },
+
+  /**
+   * Trigger new attribute field for input.
+   */
+  addAttribute: function () {
+    this.editor.newAttr.editMode();
+  },
+
+  /**
+   * Trigger attribute field for editing.
+   */
+  editAttribute: function (attrName) {
+    this.editor.attrElements.get(attrName).editMode();
+  },
+
+  /**
+   * Remove attribute from container.
+   * This is an undoable action.
+   */
+  removeAttribute: function (attrName) {
+    let doMods = this.editor._startModifyingAttributes();
+    let undoMods = this.editor._startModifyingAttributes();
+    this.editor._saveAttribute(attrName, undoMods);
+    doMods.removeAttribute(attrName);
+    this.undo.do(() => {
+      doMods.apply();
+    }, () => {
+      undoMods.apply();
+    });
+  }
+});
+
+module.exports = MarkupElementContainer;
diff --git a/devtools/client/inspector/markup/views/element-editor.js b/devtools/client/inspector/markup/views/element-editor.js
new file mode 100644
index 000000000..3149086eb
--- /dev/null
+++ b/devtools/client/inspector/markup/views/element-editor.js
@@ -0,0 +1,560 @@
+/* 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";
+
+const Services = require("Services");
+const TextEditor = require("devtools/client/inspector/markup/views/text-editor");
+const {
+  getAutocompleteMaxWidth,
+  flashElementOn,
+  flashElementOff,
+  parseAttributeValues,
+  truncateString,
+} = require("devtools/client/inspector/markup/utils");
+const {editableField, InplaceEditor} =
+      require("devtools/client/shared/inplace-editor");
+const {parseAttribute} =
+      require("devtools/client/shared/node-attribute-parser");
+const {getCssProperties} = require("devtools/shared/fronts/css-properties");
+
+// Page size for pageup/pagedown
+const COLLAPSE_DATA_URL_REGEX = /^data.+base64/;
+const COLLAPSE_DATA_URL_LENGTH = 60;
+
+// Contains only void (without end tag) HTML elements
+const HTML_VOID_ELEMENTS = [ "area", "base", "br", "col", "command", "embed",
+  "hr", "img", "input", "keygen", "link", "meta", "param", "source",
+  "track", "wbr" ];
+
+/**
+ * Creates an editor for an Element node.
+ *
+ * @param  {MarkupContainer} container
+ *         The container owning this editor.
+ * @param  {Element} node
+ *         The node being edited.
+ */
+function ElementEditor(container, node) {
+  this.container = container;
+  this.node = node;
+  this.markup = this.container.markup;
+  this.template = this.markup.template.bind(this.markup);
+  this.doc = this.markup.doc;
+  this._cssProperties = getCssProperties(this.markup.toolbox);
+
+  this.attrElements = new Map();
+  this.animationTimers = {};
+
+  // The templates will fill the following properties
+  this.elt = null;
+  this.tag = null;
+  this.closeTag = null;
+  this.attrList = null;
+  this.newAttr = null;
+  this.closeElt = null;
+
+  // Create the main editor
+  this.template("element", this);
+
+  // Make the tag name editable (unless this is a remote node or
+  // a document element)
+  if (!node.isDocumentElement) {
+    // Make the tag optionally tabbable but not by default.
+    this.tag.setAttribute("tabindex", "-1");
+    editableField({
+      element: this.tag,
+      multiline: true,
+      maxWidth: () => getAutocompleteMaxWidth(this.tag, this.container.elt),
+      trigger: "dblclick",
+      stopOnReturn: true,
+      done: this.onTagEdit.bind(this),
+      contextMenu: this.markup.inspector.onTextBoxContextMenu,
+      cssProperties: this._cssProperties
+    });
+  }
+
+  // Make the new attribute space editable.
+  this.newAttr.editMode = editableField({
+    element: this.newAttr,
+    multiline: true,
+    maxWidth: () => getAutocompleteMaxWidth(this.newAttr, this.container.elt),
+    trigger: "dblclick",
+    stopOnReturn: true,
+    contentType: InplaceEditor.CONTENT_TYPES.CSS_MIXED,
+    popup: this.markup.popup,
+    done: (val, commit) => {
+      if (!commit) {
+        return;
+      }
+
+      let doMods = this._startModifyingAttributes();
+      let undoMods = this._startModifyingAttributes();
+      this._applyAttributes(val, null, doMods, undoMods);
+      this.container.undo.do(() => {
+        doMods.apply();
+      }, function () {
+        undoMods.apply();
+      });
+    },
+    contextMenu: this.markup.inspector.onTextBoxContextMenu,
+    cssProperties: this._cssProperties
+  });
+
+  let displayName = this.node.displayName;
+  this.tag.textContent = displayName;
+  this.closeTag.textContent = displayName;
+
+  let isVoidElement = HTML_VOID_ELEMENTS.includes(displayName);
+  if (node.isInHTMLDocument && isVoidElement) {
+    this.elt.classList.add("void-element");
+  }
+
+  this.update();
+  this.initialized = true;
+}
+
+ElementEditor.prototype = {
+  set selected(value) {
+    if (this.textEditor) {
+      this.textEditor.selected = value;
+    }
+  },
+
+  flashAttribute: function (attrName) {
+    if (this.animationTimers[attrName]) {
+      clearTimeout(this.animationTimers[attrName]);
+    }
+
+    flashElementOn(this.getAttributeElement(attrName));
+
+    this.animationTimers[attrName] = setTimeout(() => {
+      flashElementOff(this.getAttributeElement(attrName));
+    }, this.markup.CONTAINER_FLASHING_DURATION);
+  },
+
+  /**
+   * Returns information about node in the editor.
+   *
+   * @param  {DOMNode} node
+   *         The node to get information from.
+   * @return {Object} An object literal with the following information:
+   *         {type: "attribute", name: "rel", value: "index", el: node}
+   */
+  getInfoAtNode: function (node) {
+    if (!node) {
+      return null;
+    }
+
+    let type = null;
+    let name = null;
+    let value = null;
+
+    // Attribute
+    let attribute = node.closest(".attreditor");
+    if (attribute) {
+      type = "attribute";
+      name = attribute.querySelector(".attr-name").textContent;
+      value = attribute.querySelector(".attr-value").textContent;
+    }
+
+    return {type, name, value, el: node};
+  },
+
+  /**
+   * Update the state of the editor from the node.
+   */
+  update: function () {
+    let nodeAttributes = this.node.attributes || [];
+
+    // Keep the data model in sync with attributes on the node.
+    let currentAttributes = new Set(nodeAttributes.map(a => a.name));
+    for (let name of this.attrElements.keys()) {
+      if (!currentAttributes.has(name)) {
+        this.removeAttribute(name);
+      }
+    }
+
+    // Only loop through the current attributes on the node.  Missing
+    // attributes have already been removed at this point.
+    for (let attr of nodeAttributes) {
+      let el = this.attrElements.get(attr.name);
+      let valueChanged = el &&
+        el.dataset.value !== attr.value;
+      let isEditing = el && el.querySelector(".editable").inplaceEditor;
+      let canSimplyShowEditor = el && (!valueChanged || isEditing);
+
+      if (canSimplyShowEditor) {
+        // Element already exists and doesn't need to be recreated.
+        // Just show it (it's hidden by default due to the template).
+        el.style.removeProperty("display");
+      } else {
+        // Create a new editor, because the value of an existing attribute
+        // has changed.
+        let attribute = this._createAttribute(attr, el);
+        attribute.style.removeProperty("display");
+
+        // Temporarily flash the attribute to highlight the change.
+        // But not if this is the first time the editor instance has
+        // been created.
+        if (this.initialized) {
+          this.flashAttribute(attr.name);
+        }
+      }
+    }
+
+    // Update the event bubble display
+    this.eventNode.style.display = this.node.hasEventListeners ?
+      "inline-block" : "none";
+
+    this.updateTextEditor();
+  },
+
+  /**
+   * Update the inline text editor in case of a single text child node.
+   */
+  updateTextEditor: function () {
+    let node = this.node.inlineTextChild;
+
+    if (this.textEditor && this.textEditor.node != node) {
+      this.elt.removeChild(this.textEditor.elt);
+      this.textEditor = null;
+    }
+
+    if (node && !this.textEditor) {
+      // Create a text editor added to this editor.
+      // This editor won't receive an update automatically, so we rely on
+      // child text editors to let us know that we need updating.
+      this.textEditor = new TextEditor(this.container, node, "text");
+      this.elt.insertBefore(this.textEditor.elt,
+                            this.elt.firstChild.nextSibling.nextSibling);
+    }
+
+    if (this.textEditor) {
+      this.textEditor.update();
+    }
+  },
+
+  _startModifyingAttributes: function () {
+    return this.node.startModifyingAttributes();
+  },
+
+  /**
+   * Get the element used for one of the attributes of this element.
+   *
+   * @param  {String} attrName
+   *         The name of the attribute to get the element for
+   * @return {DOMNode}
+   */
+  getAttributeElement: function (attrName) {
+    return this.attrList.querySelector(
+      ".attreditor[data-attr=" + CSS.escape(attrName) + "] .attr-value");
+  },
+
+  /**
+   * Remove an attribute from the attrElements object and the DOM.
+   *
+   * @param  {String} attrName
+   *         The name of the attribute to remove
+   */
+  removeAttribute: function (attrName) {
+    let attr = this.attrElements.get(attrName);
+    if (attr) {
+      this.attrElements.delete(attrName);
+      attr.remove();
+    }
+  },
+
+  _createAttribute: function (attribute, before = null) {
+    // Create the template editor, which will save some variables here.
+    let data = {
+      attrName: attribute.name,
+      attrValue: attribute.value,
+      tabindex: this.container.canFocus ? "0" : "-1",
+    };
+    this.template("attribute", data);
+    let {attr, inner, name, val} = data;
+
+    // Double quotes need to be handled specially to prevent DOMParser failing.
+    // name="v"a"l"u"e" when editing -> name='v"a"l"u"e"'
+    // name="v'a"l'u"e" when editing -> name="v'a"l'u"e"
+    let editValueDisplayed = attribute.value || "";
+    let hasDoubleQuote = editValueDisplayed.includes('"');
+    let hasSingleQuote = editValueDisplayed.includes("'");
+    let initial = attribute.name + '="' + editValueDisplayed + '"';
+
+    // Can't just wrap value with ' since the value contains both " and '.
+    if (hasDoubleQuote && hasSingleQuote) {
+      editValueDisplayed = editValueDisplayed.replace(/\"/g, """);
+      initial = attribute.name + '="' + editValueDisplayed + '"';
+    }
+
+    // Wrap with ' since there are no single quotes in the attribute value.
+    if (hasDoubleQuote && !hasSingleQuote) {
+      initial = attribute.name + "='" + editValueDisplayed + "'";
+    }
+
+    // Make the attribute editable.
+    attr.editMode = editableField({
+      element: inner,
+      trigger: "dblclick",
+      stopOnReturn: true,
+      selectAll: false,
+      initial: initial,
+      multiline: true,
+      maxWidth: () => getAutocompleteMaxWidth(inner, this.container.elt),
+      contentType: InplaceEditor.CONTENT_TYPES.CSS_MIXED,
+      popup: this.markup.popup,
+      start: (editor, event) => {
+        // If the editing was started inside the name or value areas,
+        // select accordingly.
+        if (event && event.target === name) {
+          editor.input.setSelectionRange(0, name.textContent.length);
+        } else if (event && event.target.closest(".attr-value") === val) {
+          let length = editValueDisplayed.length;
+          let editorLength = editor.input.value.length;
+          let start = editorLength - (length + 1);
+          editor.input.setSelectionRange(start, start + length);
+        } else {
+          editor.input.select();
+        }
+      },
+      done: (newValue, commit, direction) => {
+        if (!commit || newValue === initial) {
+          return;
+        }
+
+        let doMods = this._startModifyingAttributes();
+        let undoMods = this._startModifyingAttributes();
+
+        // Remove the attribute stored in this editor and re-add any attributes
+        // parsed out of the input element. Restore original attribute if
+        // parsing fails.
+        this.refocusOnEdit(attribute.name, attr, direction);
+        this._saveAttribute(attribute.name, undoMods);
+        doMods.removeAttribute(attribute.name);
+        this._applyAttributes(newValue, attr, doMods, undoMods);
+        this.container.undo.do(() => {
+          doMods.apply();
+        }, () => {
+          undoMods.apply();
+        });
+      },
+      contextMenu: this.markup.inspector.onTextBoxContextMenu,
+      cssProperties: this._cssProperties
+    });
+
+    // Figure out where we should place the attribute.
+    if (attribute.name == "id") {
+      before = this.attrList.firstChild;
+    } else if (attribute.name == "class") {
+      let idNode = this.attrElements.get("id");
+      before = idNode ? idNode.nextSibling : this.attrList.firstChild;
+    }
+    this.attrList.insertBefore(attr, before);
+
+    this.removeAttribute(attribute.name);
+    this.attrElements.set(attribute.name, attr);
+
+    // Parse the attribute value to detect whether there are linkable parts in
+    // it (make sure to pass a complete list of existing attributes to the
+    // parseAttribute function, by concatenating attribute, because this could
+    // be a newly added attribute not yet on this.node).
+    let attributes = this.node.attributes.filter(existingAttribute => {
+      return existingAttribute.name !== attribute.name;
+    });
+    attributes.push(attribute);
+    let parsedLinksData = parseAttribute(this.node.namespaceURI,
+      this.node.tagName, attributes, attribute.name);
+
+    // Create links in the attribute value, and collapse long attributes if
+    // needed.
+    let collapse = value => {
+      if (value && value.match(COLLAPSE_DATA_URL_REGEX)) {
+        return truncateString(value, COLLAPSE_DATA_URL_LENGTH);
+      }
+      return this.markup.collapseAttributes
+        ? truncateString(value, this.markup.collapseAttributeLength)
+        : value;
+    };
+
+    val.innerHTML = "";
+    for (let token of parsedLinksData) {
+      if (token.type === "string") {
+        val.appendChild(this.doc.createTextNode(collapse(token.value)));
+      } else {
+        let link = this.doc.createElement("span");
+        link.classList.add("link");
+        link.setAttribute("data-type", token.type);
+        link.setAttribute("data-link", token.value);
+        link.textContent = collapse(token.value);
+        val.appendChild(link);
+      }
+    }
+
+    name.textContent = attribute.name;
+
+    return attr;
+  },
+
+  /**
+   * Parse a user-entered attribute string and apply the resulting
+   * attributes to the node. This operation is undoable.
+   *
+   * @param  {String} value
+   *         The user-entered value.
+   * @param  {DOMNode} attrNode
+   *         The attribute editor that created this
+   *         set of attributes, used to place new attributes where the
+   *         user put them.
+   */
+  _applyAttributes: function (value, attrNode, doMods, undoMods) {
+    let attrs = parseAttributeValues(value, this.doc);
+    for (let attr of attrs) {
+      // Create an attribute editor next to the current attribute if needed.
+      this._createAttribute(attr, attrNode ? attrNode.nextSibling : null);
+      this._saveAttribute(attr.name, undoMods);
+      doMods.setAttribute(attr.name, attr.value);
+    }
+  },
+
+  /**
+   * Saves the current state of the given attribute into an attribute
+   * modification list.
+   */
+  _saveAttribute: function (name, undoMods) {
+    let node = this.node;
+    if (node.hasAttribute(name)) {
+      let oldValue = node.getAttribute(name);
+      undoMods.setAttribute(name, oldValue);
+    } else {
+      undoMods.removeAttribute(name);
+    }
+  },
+
+  /**
+   * Listen to mutations, and when the attribute list is regenerated
+   * try to focus on the attribute after the one that's being edited now.
+   * If the attribute order changes, go to the beginning of the attribute list.
+   */
+  refocusOnEdit: function (attrName, attrNode, direction) {
+    // Only allow one refocus on attribute change at a time, so when there's
+    // more than 1 request in parallel, the last one wins.
+    if (this._editedAttributeObserver) {
+      this.markup.inspector.off("markupmutation", this._editedAttributeObserver);
+      this._editedAttributeObserver = null;
+    }
+
+    let container = this.markup.getContainer(this.node);
+
+    let activeAttrs = [...this.attrList.childNodes]
+      .filter(el => el.style.display != "none");
+    let attributeIndex = activeAttrs.indexOf(attrNode);
+
+    let onMutations = this._editedAttributeObserver = (e, mutations) => {
+      let isDeletedAttribute = false;
+      let isNewAttribute = false;
+
+      for (let mutation of mutations) {
+        let inContainer =
+          this.markup.getContainer(mutation.target) === container;
+        if (!inContainer) {
+          continue;
+        }
+
+        let isOriginalAttribute = mutation.attributeName === attrName;
+
+        isDeletedAttribute = isDeletedAttribute || isOriginalAttribute &&
+                             mutation.newValue === null;
+        isNewAttribute = isNewAttribute || mutation.attributeName !== attrName;
+      }
+
+      let isModifiedOrder = isDeletedAttribute && isNewAttribute;
+      this._editedAttributeObserver = null;
+
+      // "Deleted" attributes are merely hidden, so filter them out.
+      let visibleAttrs = [...this.attrList.childNodes]
+        .filter(el => el.style.display != "none");
+      let activeEditor;
+      if (visibleAttrs.length > 0) {
+        if (!direction) {
+          // No direction was given; stay on current attribute.
+          activeEditor = visibleAttrs[attributeIndex];
+        } else if (isModifiedOrder) {
+          // The attribute was renamed, reordering the existing attributes.
+          // So let's go to the beginning of the attribute list for consistency.
+          activeEditor = visibleAttrs[0];
+        } else {
+          let newAttributeIndex;
+          if (isDeletedAttribute) {
+            newAttributeIndex = attributeIndex;
+          } else if (direction == Services.focus.MOVEFOCUS_FORWARD) {
+            newAttributeIndex = attributeIndex + 1;
+          } else if (direction == Services.focus.MOVEFOCUS_BACKWARD) {
+            newAttributeIndex = attributeIndex - 1;
+          }
+
+          // The number of attributes changed (deleted), or we moved through
+          // the array so check we're still within bounds.
+          if (newAttributeIndex >= 0 &&
+              newAttributeIndex <= visibleAttrs.length - 1) {
+            activeEditor = visibleAttrs[newAttributeIndex];
+          }
+        }
+      }
+
+      // Either we have no attributes left,
+      // or we just edited the last attribute and want to move on.
+      if (!activeEditor) {
+        activeEditor = this.newAttr;
+      }
+
+      // Refocus was triggered by tab or shift-tab.
+      // Continue in edit mode.
+      if (direction) {
+        activeEditor.editMode();
+      } else {
+        // Refocus was triggered by enter.
+        // Exit edit mode (but restore focus).
+        let editable = activeEditor === this.newAttr ?
+          activeEditor : activeEditor.querySelector(".editable");
+        editable.focus();
+      }
+
+      this.markup.emit("refocusedonedit");
+    };
+
+    // Start listening for mutations until we find an attributes change
+    // that modifies this attribute.
+    this.markup.inspector.once("markupmutation", onMutations);
+  },
+
+  /**
+   * Called when the tag name editor has is done editing.
+   */
+  onTagEdit: function (newTagName, isCommit) {
+    if (!isCommit ||
+        newTagName.toLowerCase() === this.node.tagName.toLowerCase() ||
+        !("editTagName" in this.markup.walker)) {
+      return;
+    }
+
+    // Changing the tagName removes the node. Make sure the replacing node gets
+    // selected afterwards.
+    this.markup.reselectOnRemoved(this.node, "edittagname");
+    this.markup.walker.editTagName(this.node, newTagName).then(null, () => {
+      // Failed to edit the tag name, cancel the reselection.
+      this.markup.cancelReselectOnRemoved();
+    });
+  },
+
+  destroy: function () {
+    for (let key in this.animationTimers) {
+      clearTimeout(this.animationTimers[key]);
+    }
+    this.animationTimers = null;
+  }
+};
+
+module.exports = ElementEditor;
diff --git a/devtools/client/inspector/markup/views/html-editor.js b/devtools/client/inspector/markup/views/html-editor.js
new file mode 100644
index 000000000..6f99391b6
--- /dev/null
+++ b/devtools/client/inspector/markup/views/html-editor.js
@@ -0,0 +1,180 @@
+/* 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";
+
+const Editor = require("devtools/client/sourceeditor/editor");
+const Services = require("Services");
+const EventEmitter = require("devtools/shared/event-emitter");
+
+/**
+ * A wrapper around the Editor component, that allows editing of HTML.
+ *
+ * The main functionality this provides around the Editor is the ability
+ * to show/hide/position an editor inplace. It only appends once to the
+ * body, and uses CSS to position the editor.  The reason it is done this
+ * way is that the editor is loaded in an iframe, and calling appendChild
+ * causes it to reload.
+ *
+ * Meant to be embedded inside of an HTML page, as in markup.xhtml.
+ *
+ * @param  {HTMLDocument} htmlDocument
+ *         The document to attach the editor to.  Will also use this
+ *         document as a basis for listening resize events.
+ */
+function HTMLEditor(htmlDocument) {
+  this.doc = htmlDocument;
+  this.container = this.doc.createElement("div");
+  this.container.className = "html-editor theme-body";
+  this.container.style.display = "none";
+  this.editorInner = this.doc.createElement("div");
+  this.editorInner.className = "html-editor-inner";
+  this.container.appendChild(this.editorInner);
+
+  this.doc.body.appendChild(this.container);
+  this.hide = this.hide.bind(this);
+  this.refresh = this.refresh.bind(this);
+
+  EventEmitter.decorate(this);
+
+  this.doc.defaultView.addEventListener("resize",
+    this.refresh, true);
+
+  let config = {
+    mode: Editor.modes.html,
+    lineWrapping: true,
+    styleActiveLine: false,
+    extraKeys: {},
+    theme: "mozilla markup-view"
+  };
+
+  config.extraKeys[ctrl("Enter")] = this.hide;
+  config.extraKeys.F2 = this.hide;
+  config.extraKeys.Esc = this.hide.bind(this, false);
+
+  this.container.addEventListener("click", this.hide, false);
+  this.editorInner.addEventListener("click", stopPropagation, false);
+  this.editor = new Editor(config);
+
+  this.editor.appendToLocalElement(this.editorInner);
+  this.hide(false);
+}
+
+HTMLEditor.prototype = {
+
+  /**
+   * Need to refresh position by manually setting CSS values, so this will
+   * need to be called on resizes and other sizing changes.
+   */
+  refresh: function () {
+    let element = this._attachedElement;
+
+    if (element) {
+      this.container.style.top = element.offsetTop + "px";
+      this.container.style.left = element.offsetLeft + "px";
+      this.container.style.width = element.offsetWidth + "px";
+      this.container.style.height = element.parentNode.offsetHeight + "px";
+      this.editor.refresh();
+    }
+  },
+
+  /**
+   * Anchor the editor to a particular element.
+   *
+   * @param  {DOMNode} element
+   *         The element that the editor will be anchored to.
+   *         Should belong to the HTMLDocument passed into the constructor.
+   */
+  _attach: function (element) {
+    this._detach();
+    this._attachedElement = element;
+    element.classList.add("html-editor-container");
+    this.refresh();
+  },
+
+  /**
+   * Unanchor the editor from an element.
+   */
+  _detach: function () {
+    if (this._attachedElement) {
+      this._attachedElement.classList.remove("html-editor-container");
+      this._attachedElement = undefined;
+    }
+  },
+
+  /**
+   * Anchor the editor to a particular element, and show the editor.
+   *
+   * @param  {DOMNode} element
+   *         The element that the editor will be anchored to.
+   *         Should belong to the HTMLDocument passed into the constructor.
+   * @param  {String} text
+   *         Value to set the contents of the editor to
+   * @param  {Function} cb
+   *         The function to call when hiding
+   */
+  show: function (element, text) {
+    if (this._visible) {
+      return;
+    }
+
+    this._originalValue = text;
+    this.editor.setText(text);
+    this._attach(element);
+    this.container.style.display = "flex";
+    this._visible = true;
+
+    this.editor.refresh();
+    this.editor.focus();
+
+    this.emit("popupshown");
+  },
+
+  /**
+   * Hide the editor, optionally committing the changes
+   *
+   * @param  {Boolean} shouldCommit
+   *         A change will be committed by default.  If this param
+   *         strictly equals false, no change will occur.
+   */
+  hide: function (shouldCommit) {
+    if (!this._visible) {
+      return;
+    }
+
+    this.container.style.display = "none";
+    this._detach();
+
+    let newValue = this.editor.getText();
+    let valueHasChanged = this._originalValue !== newValue;
+    let preventCommit = shouldCommit === false || !valueHasChanged;
+    this._originalValue = undefined;
+    this._visible = undefined;
+    this.emit("popuphidden", !preventCommit, newValue);
+  },
+
+  /**
+   * Destroy this object and unbind all event handlers
+   */
+  destroy: function () {
+    this.doc.defaultView.removeEventListener("resize",
+      this.refresh, true);
+    this.container.removeEventListener("click", this.hide, false);
+    this.editorInner.removeEventListener("click", stopPropagation, false);
+
+    this.hide(false);
+    this.container.remove();
+    this.editor.destroy();
+  }
+};
+
+function ctrl(k) {
+  return (Services.appinfo.OS == "Darwin" ? "Cmd-" : "Ctrl-") + k;
+}
+
+function stopPropagation(e) {
+  e.stopPropagation();
+}
+
+module.exports = HTMLEditor;
diff --git a/devtools/client/inspector/markup/views/markup-container.js b/devtools/client/inspector/markup/views/markup-container.js
new file mode 100644
index 000000000..b54157242
--- /dev/null
+++ b/devtools/client/inspector/markup/views/markup-container.js
@@ -0,0 +1,720 @@
+/* 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";
+
+const {Task} = require("devtools/shared/task");
+const {KeyCodes} = require("devtools/client/shared/keycodes");
+const {flashElementOn, flashElementOff} =
+      require("devtools/client/inspector/markup/utils");
+
+const DRAG_DROP_MIN_INITIAL_DISTANCE = 10;
+
+/**
+ * The main structure for storing a document node in the markup
+ * tree.  Manages creation of the editor for the node and
+ * a <ul> for placing child elements, and expansion/collapsing
+ * of the element.
+ *
+ * This should not be instantiated directly, instead use one of:
+ *    MarkupReadOnlyContainer
+ *    MarkupTextContainer
+ *    MarkupElementContainer
+ */
+function MarkupContainer() { }
+
+/**
+ * Unique identifier used to set markup container node id.
+ * @type {Number}
+ */
+let markupContainerID = 0;
+
+MarkupContainer.prototype = {
+  /*
+   * Initialize the MarkupContainer.  Should be called while one
+   * of the other contain classes is instantiated.
+   *
+   * @param  {MarkupView} markupView
+   *         The markup view that owns this container.
+   * @param  {NodeFront} node
+   *         The node to display.
+   * @param  {String} templateID
+   *         Which template to render for this container
+   */
+  initialize: function (markupView, node, templateID) {
+    this.markup = markupView;
+    this.node = node;
+    this.undo = this.markup.undo;
+    this.win = this.markup._frame.contentWindow;
+    this.id = "treeitem-" + markupContainerID++;
+    this.htmlElt = this.win.document.documentElement;
+
+    // The template will fill the following properties
+    this.elt = null;
+    this.expander = null;
+    this.tagState = null;
+    this.tagLine = null;
+    this.children = null;
+    this.markup.template(templateID, this);
+    this.elt.container = this;
+
+    this._onMouseDown = this._onMouseDown.bind(this);
+    this._onToggle = this._onToggle.bind(this);
+    this._onMouseUp = this._onMouseUp.bind(this);
+    this._onMouseMove = this._onMouseMove.bind(this);
+    this._onKeyDown = this._onKeyDown.bind(this);
+
+    // Binding event listeners
+    this.elt.addEventListener("mousedown", this._onMouseDown, false);
+    this.win.addEventListener("mouseup", this._onMouseUp, true);
+    this.win.addEventListener("mousemove", this._onMouseMove, true);
+    this.elt.addEventListener("dblclick", this._onToggle, false);
+    if (this.expander) {
+      this.expander.addEventListener("click", this._onToggle, false);
+    }
+
+    // Marking the node as shown or hidden
+    this.updateIsDisplayed();
+  },
+
+  toString: function () {
+    return "[MarkupContainer for " + this.node + "]";
+  },
+
+  isPreviewable: function () {
+    if (this.node.tagName && !this.node.isPseudoElement) {
+      let tagName = this.node.tagName.toLowerCase();
+      let srcAttr = this.editor.getAttributeElement("src");
+      let isImage = tagName === "img" && srcAttr;
+      let isCanvas = tagName === "canvas";
+
+      return isImage || isCanvas;
+    }
+
+    return false;
+  },
+
+  /**
+   * Show whether the element is displayed or not
+   * If an element has the attribute `display: none` or has been hidden with
+   * the H key, it is not displayed (faded in markup view).
+   * Otherwise, it is displayed.
+   */
+  updateIsDisplayed: function () {
+    this.elt.classList.remove("not-displayed");
+    if (!this.node.isDisplayed || this.node.hidden) {
+      this.elt.classList.add("not-displayed");
+    }
+  },
+
+  /**
+   * True if the current node has children. The MarkupView
+   * will set this attribute for the MarkupContainer.
+   */
+  _hasChildren: false,
+
+  get hasChildren() {
+    return this._hasChildren;
+  },
+
+  set hasChildren(value) {
+    this._hasChildren = value;
+    this.updateExpander();
+  },
+
+  /**
+   * A list of all elements with tabindex that are not in container's children.
+   */
+  get focusableElms() {
+    return [...this.tagLine.querySelectorAll("[tabindex]")];
+  },
+
+  /**
+   * An indicator that the container internals are focusable.
+   */
+  get canFocus() {
+    return this._canFocus;
+  },
+
+  /**
+   * Toggle focusable state for container internals.
+   */
+  set canFocus(value) {
+    if (this._canFocus === value) {
+      return;
+    }
+
+    this._canFocus = value;
+
+    if (value) {
+      this.tagLine.addEventListener("keydown", this._onKeyDown, true);
+      this.focusableElms.forEach(elm => elm.setAttribute("tabindex", "0"));
+    } else {
+      this.tagLine.removeEventListener("keydown", this._onKeyDown, true);
+      // Exclude from tab order.
+      this.focusableElms.forEach(elm => elm.setAttribute("tabindex", "-1"));
+    }
+  },
+
+  /**
+   * If conatiner and its contents are focusable, exclude them from tab order,
+   * and, if necessary, remove focus.
+   */
+  clearFocus: function () {
+    if (!this.canFocus) {
+      return;
+    }
+
+    this.canFocus = false;
+    let doc = this.markup.doc;
+
+    if (!doc.activeElement || doc.activeElement === doc.body) {
+      return;
+    }
+
+    let parent = doc.activeElement;
+
+    while (parent && parent !== this.elt) {
+      parent = parent.parentNode;
+    }
+
+    if (parent) {
+      doc.activeElement.blur();
+    }
+  },
+
+  /**
+   * True if the current node can be expanded.
+   */
+  get canExpand() {
+    return this._hasChildren && !this.node.inlineTextChild;
+  },
+
+  /**
+   * True if this is the root <html> element and can't be collapsed.
+   */
+  get mustExpand() {
+    return this.node._parent === this.markup.walker.rootNode;
+  },
+
+  /**
+   * True if current node can be expanded and collapsed.
+   */
+  get showExpander() {
+    return this.canExpand && !this.mustExpand;
+  },
+
+  updateExpander: function () {
+    if (!this.expander) {
+      return;
+    }
+
+    if (this.showExpander) {
+      this.expander.style.visibility = "visible";
+      // Update accessibility expanded state.
+      this.tagLine.setAttribute("aria-expanded", this.expanded);
+    } else {
+      this.expander.style.visibility = "hidden";
+      // No need for accessible expanded state indicator when expander is not
+      // shown.
+      this.tagLine.removeAttribute("aria-expanded");
+    }
+  },
+
+  /**
+   * If current node has no children, ignore them. Otherwise, consider them a
+   * group from the accessibility point of view.
+   */
+  setChildrenRole: function () {
+    this.children.setAttribute("role",
+      this.hasChildren ? "group" : "presentation");
+  },
+
+  /**
+   * Set an appropriate DOM tree depth level for a node and its subtree.
+   */
+  updateLevel: function () {
+    // ARIA level should already be set when container template is rendered.
+    let currentLevel = this.tagLine.getAttribute("aria-level");
+    let newLevel = this.level;
+    if (currentLevel === newLevel) {
+      // If level did not change, ignore this node and its subtree.
+      return;
+    }
+
+    this.tagLine.setAttribute("aria-level", newLevel);
+    let childContainers = this.getChildContainers();
+    if (childContainers) {
+      childContainers.forEach(container => container.updateLevel());
+    }
+  },
+
+  /**
+   * If the node has children, return the list of containers for all these
+   * children.
+   */
+  getChildContainers: function () {
+    if (!this.hasChildren) {
+      return null;
+    }
+
+    return [...this.children.children].filter(node => node.container)
+                                      .map(node => node.container);
+  },
+
+  /**
+   * True if the node has been visually expanded in the tree.
+   */
+  get expanded() {
+    return !this.elt.classList.contains("collapsed");
+  },
+
+  setExpanded: function (value) {
+    if (!this.expander) {
+      return;
+    }
+
+    if (!this.canExpand) {
+      value = false;
+    }
+    if (this.mustExpand) {
+      value = true;
+    }
+
+    if (value && this.elt.classList.contains("collapsed")) {
+      // Expanding a node means cloning its "inline" closing tag into a new
+      // tag-line that the user can interact with and showing the children.
+      let closingTag = this.elt.querySelector(".close");
+      if (closingTag) {
+        if (!this.closeTagLine) {
+          let line = this.markup.doc.createElement("div");
+          line.classList.add("tag-line");
+          // Closing tag is not important for accessibility.
+          line.setAttribute("role", "presentation");
+
+          let tagState = this.markup.doc.createElement("div");
+          tagState.classList.add("tag-state");
+          line.appendChild(tagState);
+
+          line.appendChild(closingTag.cloneNode(true));
+
+          flashElementOff(line);
+          this.closeTagLine = line;
+        }
+        this.elt.appendChild(this.closeTagLine);
+      }
+
+      this.elt.classList.remove("collapsed");
+      this.expander.setAttribute("open", "");
+      this.hovered = false;
+      this.markup.emit("expanded");
+    } else if (!value) {
+      if (this.closeTagLine) {
+        this.elt.removeChild(this.closeTagLine);
+        this.closeTagLine = undefined;
+      }
+      this.elt.classList.add("collapsed");
+      this.expander.removeAttribute("open");
+      this.markup.emit("collapsed");
+    }
+    if (this.showExpander) {
+      this.tagLine.setAttribute("aria-expanded", this.expanded);
+    }
+  },
+
+  parentContainer: function () {
+    return this.elt.parentNode ? this.elt.parentNode.container : null;
+  },
+
+  /**
+   * Determine tree depth level of a given node. This is used to specify ARIA
+   * level for node tree items and to give them better semantic context.
+   */
+  get level() {
+    let level = 1;
+    let parent = this.node.parentNode();
+    while (parent && parent !== this.markup.walker.rootNode) {
+      level++;
+      parent = parent.parentNode();
+    }
+    return level;
+  },
+
+  _isDragging: false,
+  _dragStartY: 0,
+
+  set isDragging(isDragging) {
+    let rootElt = this.markup.getContainer(this.markup._rootNode).elt;
+    this._isDragging = isDragging;
+    this.markup.isDragging = isDragging;
+    this.tagLine.setAttribute("aria-grabbed", isDragging);
+
+    if (isDragging) {
+      this.htmlElt.classList.add("dragging");
+      this.elt.classList.add("dragging");
+      this.markup.doc.body.classList.add("dragging");
+      rootElt.setAttribute("aria-dropeffect", "move");
+    } else {
+      this.htmlElt.classList.remove("dragging");
+      this.elt.classList.remove("dragging");
+      this.markup.doc.body.classList.remove("dragging");
+      rootElt.setAttribute("aria-dropeffect", "none");
+    }
+  },
+
+  get isDragging() {
+    return this._isDragging;
+  },
+
+  /**
+   * Check if element is draggable.
+   */
+  isDraggable: function () {
+    let tagName = this.node.tagName && this.node.tagName.toLowerCase();
+
+    return !this.node.isPseudoElement &&
+           !this.node.isAnonymous &&
+           !this.node.isDocumentElement &&
+           tagName !== "body" &&
+           tagName !== "head" &&
+           this.win.getSelection().isCollapsed &&
+           this.node.parentNode().tagName !== null;
+  },
+
+  /**
+   * Move keyboard focus to a next/previous focusable element inside container
+   * that is not part of its children (only if current focus is on first or last
+   * element).
+   *
+   * @param  {DOMNode} current  currently focused element
+   * @param  {Boolean} back     direction
+   * @return {DOMNode}          newly focused element if any
+   */
+  _wrapMoveFocus: function (current, back) {
+    let elms = this.focusableElms;
+    let next;
+    if (back) {
+      if (elms.indexOf(current) === 0) {
+        next = elms[elms.length - 1];
+        next.focus();
+      }
+    } else if (elms.indexOf(current) === elms.length - 1) {
+      next = elms[0];
+      next.focus();
+    }
+    return next;
+  },
+
+  _onKeyDown: function (event) {
+    let {target, keyCode, shiftKey} = event;
+    let isInput = this.markup._isInputOrTextarea(target);
+
+    // Ignore all keystrokes that originated in editors except for when 'Tab' is
+    // pressed.
+    if (isInput && keyCode !== KeyCodes.DOM_VK_TAB) {
+      return;
+    }
+
+    switch (keyCode) {
+      case KeyCodes.DOM_VK_TAB:
+        // Only handle 'Tab' if tabbable element is on the edge (first or last).
+        if (isInput) {
+          // Corresponding tabbable element is editor's next sibling.
+          let next = this._wrapMoveFocus(target.nextSibling, shiftKey);
+          if (next) {
+            event.preventDefault();
+            // Keep the editing state if possible.
+            if (next._editable) {
+              let e = this.markup.doc.createEvent("Event");
+              e.initEvent(next._trigger, true, true);
+              next.dispatchEvent(e);
+            }
+          }
+        } else {
+          let next = this._wrapMoveFocus(target, shiftKey);
+          if (next) {
+            event.preventDefault();
+          }
+        }
+        break;
+      case KeyCodes.DOM_VK_ESCAPE:
+        this.clearFocus();
+        this.markup.getContainer(this.markup._rootNode).elt.focus();
+        if (this.isDragging) {
+          // Escape when dragging is handled by markup view itself.
+          return;
+        }
+        event.preventDefault();
+        break;
+      default:
+        return;
+    }
+    event.stopPropagation();
+  },
+
+  _onMouseDown: function (event) {
+    let {target, button, metaKey, ctrlKey} = event;
+    let isLeftClick = button === 0;
+    let isMiddleClick = button === 1;
+    let isMetaClick = isLeftClick && (metaKey || ctrlKey);
+
+    // The "show more nodes" button already has its onclick, so early return.
+    if (target.nodeName === "button") {
+      return;
+    }
+
+    // target is the MarkupContainer itself.
+    this.hovered = false;
+    this.markup.navigate(this);
+    // Make container tabbable descendants tabbable and focus in.
+    this.canFocus = true;
+    this.focus();
+    event.stopPropagation();
+
+    // Preventing the default behavior will avoid the body to gain focus on
+    // mouseup (through bubbling) when clicking on a non focusable node in the
+    // line. So, if the click happened outside of a focusable element, do
+    // prevent the default behavior, so that the tagname or textcontent gains
+    // focus.
+    if (!target.closest(".editor [tabindex]")) {
+      event.preventDefault();
+    }
+
+    // Follow attribute links if middle or meta click.
+    if (isMiddleClick || isMetaClick) {
+      let link = target.dataset.link;
+      let type = target.dataset.type;
+      // Make container tabbable descendants not tabbable (by default).
+      this.canFocus = false;
+      this.markup.inspector.followAttributeLink(type, link);
+      return;
+    }
+
+    // Start node drag & drop (if the mouse moved, see _onMouseMove).
+    if (isLeftClick && this.isDraggable()) {
+      this._isPreDragging = true;
+      this._dragStartY = event.pageY;
+    }
+  },
+
+  /**
+   * On mouse up, stop dragging.
+   */
+  _onMouseUp: Task.async(function* () {
+    this._isPreDragging = false;
+
+    if (this.isDragging) {
+      this.cancelDragging();
+
+      let dropTargetNodes = this.markup.dropTargetNodes;
+
+      if (!dropTargetNodes) {
+        return;
+      }
+
+      yield this.markup.walker.insertBefore(this.node, dropTargetNodes.parent,
+                                            dropTargetNodes.nextSibling);
+      this.markup.emit("drop-completed");
+    }
+  }),
+
+  /**
+   * On mouse move, move the dragged element and indicate the drop target.
+   */
+  _onMouseMove: function (event) {
+    // If this is the first move after mousedown, only start dragging after the
+    // mouse has travelled a few pixels and then indicate the start position.
+    let initialDiff = Math.abs(event.pageY - this._dragStartY);
+    if (this._isPreDragging && initialDiff >= DRAG_DROP_MIN_INITIAL_DISTANCE) {
+      this._isPreDragging = false;
+      this.isDragging = true;
+
+      // If this is the last child, use the closing <div.tag-line> of parent as
+      // indicator.
+      let position = this.elt.nextElementSibling ||
+                     this.markup.getContainer(this.node.parentNode())
+                                .closeTagLine;
+      this.markup.indicateDragTarget(position);
+    }
+
+    if (this.isDragging) {
+      let x = 0;
+      let y = event.pageY - this.win.scrollY;
+
+      // Ensure we keep the dragged element within the markup view.
+      if (y < 0) {
+        y = 0;
+      } else if (y >= this.markup.doc.body.offsetHeight - this.win.scrollY) {
+        y = this.markup.doc.body.offsetHeight - this.win.scrollY - 1;
+      }
+
+      let diff = y - this._dragStartY + this.win.scrollY;
+      this.elt.style.top = diff + "px";
+
+      let el = this.markup.doc.elementFromPoint(x, y);
+      this.markup.indicateDropTarget(el);
+    }
+  },
+
+  cancelDragging: function () {
+    if (!this.isDragging) {
+      return;
+    }
+
+    this._isPreDragging = false;
+    this.isDragging = false;
+    this.elt.style.removeProperty("top");
+  },
+
+  /**
+   * Temporarily flash the container to attract attention.
+   * Used for markup mutations.
+   */
+  flashMutation: function () {
+    if (!this.selected) {
+      flashElementOn(this.tagState, this.editor.elt);
+      if (this._flashMutationTimer) {
+        clearTimeout(this._flashMutationTimer);
+        this._flashMutationTimer = null;
+      }
+      this._flashMutationTimer = setTimeout(() => {
+        flashElementOff(this.tagState, this.editor.elt);
+      }, this.markup.CONTAINER_FLASHING_DURATION);
+    }
+  },
+
+  _hovered: false,
+
+  /**
+   * Highlight the currently hovered tag + its closing tag if necessary
+   * (that is if the tag is expanded)
+   */
+  set hovered(value) {
+    this.tagState.classList.remove("flash-out");
+    this._hovered = value;
+    if (value) {
+      if (!this.selected) {
+        this.tagState.classList.add("theme-bg-darker");
+      }
+      if (this.closeTagLine) {
+        this.closeTagLine.querySelector(".tag-state").classList.add(
+          "theme-bg-darker");
+      }
+    } else {
+      this.tagState.classList.remove("theme-bg-darker");
+      if (this.closeTagLine) {
+        this.closeTagLine.querySelector(".tag-state").classList.remove(
+          "theme-bg-darker");
+      }
+    }
+  },
+
+  /**
+   * True if the container is visible in the markup tree.
+   */
+  get visible() {
+    return this.elt.getBoundingClientRect().height > 0;
+  },
+
+  /**
+   * True if the container is currently selected.
+   */
+  _selected: false,
+
+  get selected() {
+    return this._selected;
+  },
+
+  set selected(value) {
+    this.tagState.classList.remove("flash-out");
+    this._selected = value;
+    this.editor.selected = value;
+    // Markup tree item should have accessible selected state.
+    this.tagLine.setAttribute("aria-selected", value);
+    if (this._selected) {
+      let container = this.markup.getContainer(this.markup._rootNode);
+      if (container) {
+        container.elt.setAttribute("aria-activedescendant", this.id);
+      }
+      this.tagLine.setAttribute("selected", "");
+      this.tagState.classList.add("theme-selected");
+    } else {
+      this.tagLine.removeAttribute("selected");
+      this.tagState.classList.remove("theme-selected");
+    }
+  },
+
+  /**
+   * Update the container's editor to the current state of the
+   * viewed node.
+   */
+  update: function () {
+    if (this.node.pseudoClassLocks.length) {
+      this.elt.classList.add("pseudoclass-locked");
+    } else {
+      this.elt.classList.remove("pseudoclass-locked");
+    }
+
+    if (this.editor.update) {
+      this.editor.update();
+    }
+  },
+
+  /**
+   * Try to put keyboard focus on the current editor.
+   */
+  focus: function () {
+    // Elements with tabindex of -1 are not focusable.
+    let focusable = this.editor.elt.querySelector("[tabindex='0']");
+    if (focusable) {
+      focusable.focus();
+    }
+  },
+
+  _onToggle: function (event) {
+    this.markup.navigate(this);
+    if (this.hasChildren) {
+      this.markup.setNodeExpanded(this.node, !this.expanded, event.altKey);
+    }
+    event.stopPropagation();
+  },
+
+  /**
+   * Get rid of event listeners and references, when the container is no longer
+   * needed
+   */
+  destroy: function () {
+    // Remove event listeners
+    this.elt.removeEventListener("mousedown", this._onMouseDown, false);
+    this.elt.removeEventListener("dblclick", this._onToggle, false);
+    this.tagLine.removeEventListener("keydown", this._onKeyDown, true);
+    if (this.win) {
+      this.win.removeEventListener("mouseup", this._onMouseUp, true);
+      this.win.removeEventListener("mousemove", this._onMouseMove, true);
+    }
+
+    this.win = null;
+    this.htmlElt = null;
+
+    if (this.expander) {
+      this.expander.removeEventListener("click", this._onToggle, false);
+    }
+
+    // Recursively destroy children containers
+    let firstChild = this.children.firstChild;
+    while (firstChild) {
+      // Not all children of a container are containers themselves
+      // ("show more nodes" button is one example)
+      if (firstChild.container) {
+        firstChild.container.destroy();
+      }
+      this.children.removeChild(firstChild);
+      firstChild = this.children.firstChild;
+    }
+
+    this.editor.destroy();
+  }
+};
+
+module.exports = MarkupContainer;
diff --git a/devtools/client/inspector/markup/views/moz.build b/devtools/client/inspector/markup/views/moz.build
new file mode 100644
index 000000000..846bc6a84
--- /dev/null
+++ b/devtools/client/inspector/markup/views/moz.build
@@ -0,0 +1,17 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+DevToolsModules(
+    'element-container.js',
+    'element-editor.js',
+    'html-editor.js',
+    'markup-container.js',
+    'read-only-container.js',
+    'read-only-editor.js',
+    'root-container.js',
+    'text-container.js',
+    'text-editor.js',
+)
diff --git a/devtools/client/inspector/markup/views/read-only-container.js b/devtools/client/inspector/markup/views/read-only-container.js
new file mode 100644
index 000000000..fd645baac
--- /dev/null
+++ b/devtools/client/inspector/markup/views/read-only-container.js
@@ -0,0 +1,33 @@
+/* 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";
+
+const Heritage = require("sdk/core/heritage");
+const ReadOnlyEditor = require("devtools/client/inspector/markup/views/read-only-editor");
+const MarkupContainer = require("devtools/client/inspector/markup/views/markup-container");
+
+/**
+ * An implementation of MarkupContainer for Pseudo Elements,
+ * Doctype nodes, or any other type generic node that doesn't
+ * fit for other editors.
+ * Does not allow any editing, just viewing / selecting.
+ *
+ * @param  {MarkupView} markupView
+ *         The markup view that owns this container.
+ * @param  {NodeFront} node
+ *         The node to display.
+ */
+function MarkupReadOnlyContainer(markupView, node) {
+  MarkupContainer.prototype.initialize.call(this, markupView, node,
+    "readonlycontainer");
+
+  this.editor = new ReadOnlyEditor(this, node);
+  this.tagLine.appendChild(this.editor.elt);
+}
+
+MarkupReadOnlyContainer.prototype =
+  Heritage.extend(MarkupContainer.prototype, {});
+
+module.exports = MarkupReadOnlyContainer;
diff --git a/devtools/client/inspector/markup/views/read-only-editor.js b/devtools/client/inspector/markup/views/read-only-editor.js
new file mode 100644
index 000000000..dbc39eeb7
--- /dev/null
+++ b/devtools/client/inspector/markup/views/read-only-editor.js
@@ -0,0 +1,43 @@
+/* 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";
+
+const nodeConstants = require("devtools/shared/dom-node-constants");
+
+/**
+ * Creates an editor for non-editable nodes.
+ */
+function ReadOnlyEditor(container, node) {
+  this.container = container;
+  this.markup = this.container.markup;
+  this.template = this.markup.template.bind(this.markup);
+  this.elt = null;
+  this.template("generic", this);
+
+  if (node.isPseudoElement) {
+    this.tag.classList.add("theme-fg-color5");
+    this.tag.textContent = node.isBeforePseudoElement ? "::before" : "::after";
+  } else if (node.nodeType == nodeConstants.DOCUMENT_TYPE_NODE) {
+    this.elt.classList.add("comment");
+    this.tag.textContent = node.doctypeString;
+  } else {
+    this.tag.textContent = node.nodeName;
+  }
+}
+
+ReadOnlyEditor.prototype = {
+  destroy: function () {
+    this.elt.remove();
+  },
+
+  /**
+   * Stub method for consistency with ElementEditor.
+   */
+  getInfoAtNode: function () {
+    return null;
+  }
+};
+
+module.exports = ReadOnlyEditor;
diff --git a/devtools/client/inspector/markup/views/root-container.js b/devtools/client/inspector/markup/views/root-container.js
new file mode 100644
index 000000000..ccc918fca
--- /dev/null
+++ b/devtools/client/inspector/markup/views/root-container.js
@@ -0,0 +1,55 @@
+/* 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";
+
+/**
+ * Dummy container node used for the root document element.
+ */
+function RootContainer(markupView, node) {
+  this.doc = markupView.doc;
+  this.elt = this.doc.createElement("ul");
+  // Root container has tree semantics for accessibility.
+  this.elt.setAttribute("role", "tree");
+  this.elt.setAttribute("tabindex", "0");
+  this.elt.setAttribute("aria-dropeffect", "none");
+  this.elt.container = this;
+  this.children = this.elt;
+  this.node = node;
+  this.toString = () => "[root container]";
+}
+
+RootContainer.prototype = {
+  hasChildren: true,
+  expanded: true,
+  update: function () {},
+  destroy: function () {},
+
+  /**
+   * If the node has children, return the list of containers for all these children.
+   * @return {Array} An array of child containers or null.
+   */
+  getChildContainers: function () {
+    return [...this.children.children].filter(node => node.container)
+                                      .map(node => node.container);
+  },
+
+  /**
+   * Set the expanded state of the container node.
+   * @param  {Boolean} value
+   */
+  setExpanded: function () {},
+
+  /**
+   * Set an appropriate role of the container's children node.
+   */
+  setChildrenRole: function () {},
+
+  /**
+   * Set an appropriate DOM tree depth level for a node and its subtree.
+   */
+  updateLevel: function () {}
+};
+
+module.exports = RootContainer;
diff --git a/devtools/client/inspector/markup/views/text-container.js b/devtools/client/inspector/markup/views/text-container.js
new file mode 100644
index 000000000..357f17778
--- /dev/null
+++ b/devtools/client/inspector/markup/views/text-container.js
@@ -0,0 +1,40 @@
+/* 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";
+
+const Heritage = require("sdk/core/heritage");
+const nodeConstants = require("devtools/shared/dom-node-constants");
+const TextEditor = require("devtools/client/inspector/markup/views/text-editor");
+const MarkupContainer = require("devtools/client/inspector/markup/views/markup-container");
+
+/**
+ * An implementation of MarkupContainer for text node and comment nodes.
+ * Allows basic text editing in a textarea.
+ *
+ * @param  {MarkupView} markupView
+ *         The markup view that owns this container.
+ * @param  {NodeFront} node
+ *         The node to display.
+ * @param  {Inspector} inspector
+ *         The inspector tool container the markup-view
+ */
+function MarkupTextContainer(markupView, node) {
+  MarkupContainer.prototype.initialize.call(this, markupView, node,
+    "textcontainer");
+
+  if (node.nodeType == nodeConstants.TEXT_NODE) {
+    this.editor = new TextEditor(this, node, "text");
+  } else if (node.nodeType == nodeConstants.COMMENT_NODE) {
+    this.editor = new TextEditor(this, node, "comment");
+  } else {
+    throw new Error("Invalid node for MarkupTextContainer");
+  }
+
+  this.tagLine.appendChild(this.editor.elt);
+}
+
+MarkupTextContainer.prototype = Heritage.extend(MarkupContainer.prototype, {});
+
+module.exports = MarkupTextContainer;
diff --git a/devtools/client/inspector/markup/views/text-editor.js b/devtools/client/inspector/markup/views/text-editor.js
new file mode 100644
index 000000000..f3c83ca87
--- /dev/null
+++ b/devtools/client/inspector/markup/views/text-editor.js
@@ -0,0 +1,109 @@
+/* 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";
+
+const {getAutocompleteMaxWidth} = require("devtools/client/inspector/markup/utils");
+const {editableField} = require("devtools/client/shared/inplace-editor");
+const {getCssProperties} = require("devtools/shared/fronts/css-properties");
+const {LocalizationHelper} = require("devtools/shared/l10n");
+
+const INSPECTOR_L10N =
+      new LocalizationHelper("devtools/client/locales/inspector.properties");
+
+/**
+ * Creates a simple text editor node, used for TEXT and COMMENT
+ * nodes.
+ *
+ * @param  {MarkupContainer} container
+ *         The container owning this editor.
+ * @param  {DOMNode} node
+ *         The node being edited.
+ * @param  {String} templateId
+ *         The template id to use to build the editor.
+ */
+function TextEditor(container, node, templateId) {
+  this.container = container;
+  this.markup = this.container.markup;
+  this.node = node;
+  this.template = this.markup.template.bind(templateId);
+  this._selected = false;
+
+  this.markup.template(templateId, this);
+
+  editableField({
+    element: this.value,
+    stopOnReturn: true,
+    trigger: "dblclick",
+    multiline: true,
+    maxWidth: () => getAutocompleteMaxWidth(this.value, this.container.elt),
+    trimOutput: false,
+    done: (val, commit) => {
+      if (!commit) {
+        return;
+      }
+      this.node.getNodeValue().then(longstr => {
+        longstr.string().then(oldValue => {
+          longstr.release().then(null, console.error);
+
+          this.container.undo.do(() => {
+            this.node.setNodeValue(val);
+          }, () => {
+            this.node.setNodeValue(oldValue);
+          });
+        });
+      });
+    },
+    cssProperties: getCssProperties(this.markup.toolbox),
+    contextMenu: this.markup.inspector.onTextBoxContextMenu
+  });
+
+  this.update();
+}
+
+TextEditor.prototype = {
+  get selected() {
+    return this._selected;
+  },
+
+  set selected(value) {
+    if (value === this._selected) {
+      return;
+    }
+    this._selected = value;
+    this.update();
+  },
+
+  update: function () {
+    let longstr = null;
+    this.node.getNodeValue().then(ret => {
+      longstr = ret;
+      return longstr.string();
+    }).then(str => {
+      longstr.release().then(null, console.error);
+      this.value.textContent = str;
+
+      let isWhitespace = !/[^\s]/.exec(str);
+      this.value.classList.toggle("whitespace", isWhitespace);
+
+      let chars = str.replace(/\n/g, "⏎")
+                     .replace(/\t/g, "⇥")
+                     .replace(/ /g, "◦");
+      this.value.setAttribute("title", isWhitespace
+        ? INSPECTOR_L10N.getFormatStr("markupView.whitespaceOnly", chars)
+        : "");
+    }).then(null, console.error);
+  },
+
+  destroy: function () {},
+
+  /**
+   * Stub method for consistency with ElementEditor.
+   */
+  getInfoAtNode: function () {
+    return null;
+  }
+};
+
+module.exports = TextEditor;