Merge branch 'master' into configurebuild-work

22 files changed, 351 insertions, 32 deletions

diff --git a/devtools/client/inspector/inspector.js b/devtools/client/inspector/inspector.js
index c056c213f..d0458fc1f 100644
--- a/devtools/client/inspector/inspector.js
+++ b/devtools/client/inspector/inspector.js
@@ -169,6 +169,10 @@ Inspector.prototype = {
     return this._target.client.traits.getUniqueSelector;
   },
 
+  get canGetCssPath() {
+    return this._target.client.traits.getCssPath;
+  },
+
   get canGetUsedFontFaces() {
     return this._target.client.traits.getUsedFontFaces;
   },
@@ -1074,6 +1078,15 @@ Inspector.prototype = {
       click: () => this.copyUniqueSelector(),
     }));
     copySubmenu.append(new MenuItem({
+      id: "node-menu-copycsspath",
+      label: INSPECTOR_L10N.getStr("inspectorCopyCSSPath.label"),
+      accesskey:
+        INSPECTOR_L10N.getStr("inspectorCopyCSSPath.accesskey"),
+      disabled: !isSelectionElement,
+      hidden: !this.canGetCssPath,
+      click: () => this.copyCssPath(),
+    }));
+    copySubmenu.append(new MenuItem({
       id: "node-menu-copyimagedatauri",
       label: INSPECTOR_L10N.getStr("inspectorImageDataUri.label"),
       disabled: !isSelectionElement || !markupContainer ||
@@ -1677,9 +1690,24 @@ Inspector.prototype = {
       return;
     }
 
-    this.selection.nodeFront.getUniqueSelector().then((selector) => {
+    this.telemetry.toolOpened("copyuniquecssselector");
+    this.selection.nodeFront.getUniqueSelector().then(selector => {
       clipboardHelper.copyString(selector);
-    }).then(null, console.error);
+    }).catch(e => console.error);
+  },
+
+  /**
+   * Copy the full CSS Path of the selected Node to the clipboard.
+   */
+  copyCssPath: function () {
+    if (!this.selection.isNode()) {
+      return;
+    }
+
+    this.telemetry.toolOpened("copyfullcssselector");
+    this.selection.nodeFront.getCssPath().then(path => {
+      clipboardHelper.copyString(path);
+    }).catch(e => console.error);
   },
 
   /**
diff --git a/devtools/client/inspector/markup/views/markup-container.js b/devtools/client/inspector/markup/views/markup-container.js
index b54157242..44768b46c 100644
--- a/devtools/client/inspector/markup/views/markup-container.js
+++ b/devtools/client/inspector/markup/views/markup-container.js
@@ -211,10 +211,12 @@ MarkupContainer.prototype = {
     }
 
     if (this.showExpander) {
+      this.elt.classList.add("expandable");
       this.expander.style.visibility = "visible";
       // Update accessibility expanded state.
       this.tagLine.setAttribute("aria-expanded", this.expanded);
     } else {
+      this.elt.classList.remove("expandable");
       this.expander.style.visibility = "hidden";
       // No need for accessible expanded state indicator when expander is not
       // shown.
diff --git a/devtools/client/inspector/shared/tooltips-overlay.js b/devtools/client/inspector/shared/tooltips-overlay.js
index 8a02d7e3d..336dae05b 100644
--- a/devtools/client/inspector/shared/tooltips-overlay.js
+++ b/devtools/client/inspector/shared/tooltips-overlay.js
@@ -88,7 +88,9 @@ TooltipsOverlay.prototype = {
 
     if (this.isRuleView) {
       // Color picker tooltip
-      this.colorPicker = new SwatchColorPickerTooltip(toolbox.doc, this.view.inspector);
+      this.colorPicker = new SwatchColorPickerTooltip(toolbox.doc,
+                                                      this.view.inspector,
+                                                      this._cssProperties);
       // Cubic bezier tooltip
       this.cubicBezier = new SwatchCubicBezierTooltip(toolbox.doc);
       // Filter editor tooltip
diff --git a/devtools/client/inspector/test/browser_inspector_menu-01-sensitivity.js b/devtools/client/inspector/test/browser_inspector_menu-01-sensitivity.js
index 59dbbbcc0..052e9da68 100644
--- a/devtools/client/inspector/test/browser_inspector_menu-01-sensitivity.js
+++ b/devtools/client/inspector/test/browser_inspector_menu-01-sensitivity.js
@@ -26,6 +26,7 @@ const ALL_MENU_ITEMS = [
   "node-menu-copyinner",
   "node-menu-copyouter",
   "node-menu-copyuniqueselector",
+  "node-menu-copycsspath",
   "node-menu-copyimagedatauri",
   "node-menu-delete",
   "node-menu-pseudo-hover",
diff --git a/devtools/client/inspector/test/browser_inspector_menu-02-copy-items.js b/devtools/client/inspector/test/browser_inspector_menu-02-copy-items.js
index 0c96e9bbe..57a5dbaa0 100644
--- a/devtools/client/inspector/test/browser_inspector_menu-02-copy-items.js
+++ b/devtools/client/inspector/test/browser_inspector_menu-02-copy-items.js
@@ -26,6 +26,12 @@ const COPY_ITEMS_TEST_DATA = [
     text: "body > div:nth-child(1) > p:nth-child(2)",
   },
   {
+    desc: "copy css path",
+    id: "node-menu-copycsspath",
+    selector: "[data-id=\"copy\"]",
+    text: "html body div p",
+  },
+  {
     desc: "copy image data uri",
     id: "node-menu-copyimagedatauri",
     selector: "#copyimage",
diff --git a/devtools/client/locales/en-US/inspector.properties b/devtools/client/locales/en-US/inspector.properties
index 4f4829678..b6f3e072b 100644
--- a/devtools/client/locales/en-US/inspector.properties
+++ b/devtools/client/locales/en-US/inspector.properties
@@ -154,6 +154,12 @@ inspectorCopyOuterHTML.accesskey=O
 inspectorCopyCSSSelector.label=CSS Selector
 inspectorCopyCSSSelector.accesskey=S
 
+# LOCALIZATION NOTE (inspectorCopyCSSPath.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users copy
+# the full CSS path of the current node
+inspectorCopyCSSPath.label=CSS Path
+inspectorCopyCSSPath.accesskey=P
+
 # LOCALIZATION NOTE (inspectorPasteOuterHTML.label): This is the label shown
 # in the inspector contextual-menu for the item that lets users paste outer
 # HTML in the current node
diff --git a/devtools/client/shared/output-parser.js b/devtools/client/shared/output-parser.js
index 726c93b8b..b4fb1c6aa 100644
--- a/devtools/client/shared/output-parser.js
+++ b/devtools/client/shared/output-parser.js
@@ -40,8 +40,11 @@ const CSS_GRID_ENABLED_PREF = "layout.css.grid.enabled";
  *                   where CSS_TYPES is defined in devtools/shared/css/properties-db.js
  * @param {Function} isValidOnClient - A function that checks if a css property
  *                   name/value combo is valid.
+ * @param {Function} supportsCssColor4ColorFunction - A function for checking
+ *                   the supporting of css-color-4 color function.
  */
-function OutputParser(document, {supportsType, isValidOnClient}) {
+function OutputParser(document,
+                      {supportsType, isValidOnClient, supportsCssColor4ColorFunction}) {
   this.parsed = [];
   this.doc = document;
   this.supportsType = supportsType;
@@ -50,6 +53,8 @@ function OutputParser(document, {supportsType, isValidOnClient}) {
   this.angleSwatches = new WeakMap();
   this._onColorSwatchMouseDown = this._onColorSwatchMouseDown.bind(this);
   this._onAngleSwatchMouseDown = this._onAngleSwatchMouseDown.bind(this);
+
+  this.cssColor4 = supportsCssColor4ColorFunction();
 }
 
 exports.OutputParser = OutputParser;
@@ -188,7 +193,8 @@ OutputParser.prototype = {
 
             if (options.expectCubicBezier && token.text === "cubic-bezier") {
               this._appendCubicBezier(functionText, options);
-            } else if (colorOK() && colorUtils.isValidCSSColor(functionText)) {
+            } else if (colorOK() &&
+                       colorUtils.isValidCSSColor(functionText, this.cssColor4)) {
               this._appendColor(functionText, options);
             } else {
               this._appendTextNode(functionText);
@@ -205,7 +211,8 @@ OutputParser.prototype = {
                      options.expectDisplay && token.text === "grid" &&
                      text === token.text) {
             this._appendGrid(token.text, options);
-          } else if (colorOK() && colorUtils.isValidCSSColor(token.text)) {
+          } else if (colorOK() &&
+                     colorUtils.isValidCSSColor(token.text, this.cssColor4)) {
             this._appendColor(token.text, options);
           } else if (angleOK(token.text)) {
             this._appendAngle(token.text, options);
@@ -218,7 +225,7 @@ OutputParser.prototype = {
         case "id":
         case "hash": {
           let original = text.substring(token.startOffset, token.endOffset);
-          if (colorOK() && colorUtils.isValidCSSColor(original)) {
+          if (colorOK() && colorUtils.isValidCSSColor(original, this.cssColor4)) {
             this._appendColor(original, options);
           } else {
             this._appendTextNode(original);
@@ -394,7 +401,7 @@ OutputParser.prototype = {
    *         _mergeOptions().
    */
   _appendColor: function (color, options = {}) {
-    let colorObj = new colorUtils.CssColor(color);
+    let colorObj = new colorUtils.CssColor(color, this.cssColor4);
 
     if (this._isValidColor(colorObj)) {
       let container = this._createNode("span", {
diff --git a/devtools/client/shared/telemetry.js b/devtools/client/shared/telemetry.js
index 64a299581..38a21cef6 100644
--- a/devtools/client/shared/telemetry.js
+++ b/devtools/client/shared/telemetry.js
@@ -163,6 +163,12 @@ Telemetry.prototype = {
     toolbareyedropper: {
       histogram: "DEVTOOLS_TOOLBAR_EYEDROPPER_OPENED_COUNT",
     },
+    copyuniquecssselector: {
+      histogram: "DEVTOOLS_COPY_UNIQUE_CSS_SELECTOR_OPENED_COUNT",
+    },
+    copyfullcssselector: {
+      histogram: "DEVTOOLS_COPY_FULL_CSS_SELECTOR_OPENED_COUNT",
+    },
     developertoolbar: {
       histogram: "DEVTOOLS_DEVELOPERTOOLBAR_OPENED_COUNT",
       timerHistogram: "DEVTOOLS_DEVELOPERTOOLBAR_TIME_ACTIVE_SECONDS"
diff --git a/devtools/client/shared/test/unit/test_cssColor-03.js b/devtools/client/shared/test/unit/test_cssColor-03.js
index c3ef5a5c2..a081f7698 100644
--- a/devtools/client/shared/test/unit/test_cssColor-03.js
+++ b/devtools/client/shared/test/unit/test_cssColor-03.js
@@ -42,15 +42,15 @@ const CSS_COLOR_4_TESTS = [
 
 function run_test() {
   for (let test of OLD_STYLE_TESTS) {
-    let ours = colorUtils.colorToRGBA(test, true);
+    let ours = colorUtils.colorToRGBA(test, false);
     let platform = DOMUtils.colorToRGBA(test);
     deepEqual(ours, platform, "color " + test + " matches DOMUtils");
     ok(ours !== null, "'" + test + "' is a color");
   }
 
   for (let test of CSS_COLOR_4_TESTS) {
-    let oursOld = colorUtils.colorToRGBA(test, true);
-    let oursNew = colorUtils.colorToRGBA(test, false);
+    let oursOld = colorUtils.colorToRGBA(test, false);
+    let oursNew = colorUtils.colorToRGBA(test, true);
     let platform = DOMUtils.colorToRGBA(test);
     notEqual(oursOld, platform, "old style parser for color " + test +
              " should not match DOMUtils");
diff --git a/devtools/client/shared/widgets/tooltip/SwatchColorPickerTooltip.js b/devtools/client/shared/widgets/tooltip/SwatchColorPickerTooltip.js
index bf211b8b9..6a18ec12c 100644
--- a/devtools/client/shared/widgets/tooltip/SwatchColorPickerTooltip.js
+++ b/devtools/client/shared/widgets/tooltip/SwatchColorPickerTooltip.js
@@ -28,8 +28,12 @@ const XHTML_NS = "http://www.w3.org/1999/xhtml";
  *        inline editor.
  * @param {InspectorPanel} inspector
  *        The inspector panel, needed for the eyedropper.
+ * @param {Function} supportsCssColor4ColorFunction
+ *        A function for checking the supporting of css-color-4 color function.
  */
-function SwatchColorPickerTooltip(document, inspector) {
+function SwatchColorPickerTooltip(document,
+                                  inspector,
+                                  {supportsCssColor4ColorFunction}) {
   let stylesheet = "chrome://devtools/content/shared/widgets/spectrum.css";
   SwatchBasedEditorTooltip.call(this, document, stylesheet);
 
@@ -40,6 +44,7 @@ function SwatchColorPickerTooltip(document, inspector) {
   this.spectrum = this.setColorPickerContent([0, 0, 0, 1]);
   this._onSpectrumColorChange = this._onSpectrumColorChange.bind(this);
   this._openEyeDropper = this._openEyeDropper.bind(this);
+  this.cssColor4 = supportsCssColor4ColorFunction();
 }
 
 SwatchColorPickerTooltip.prototype = Heritage.extend(SwatchBasedEditorTooltip.prototype, {
@@ -159,14 +164,14 @@ SwatchColorPickerTooltip.prototype = Heritage.extend(SwatchBasedEditorTooltip.pr
   },
 
   _colorToRgba: function (color) {
-    color = new colorUtils.CssColor(color);
+    color = new colorUtils.CssColor(color, this.cssColor4);
     let rgba = color._getRGBATuple();
     return [rgba.r, rgba.g, rgba.b, rgba.a];
   },
 
   _toDefaultType: function (color) {
     let colorObj = new colorUtils.CssColor(color);
-    colorObj.setAuthoredUnitFromColor(this._originalColor);
+    colorObj.setAuthoredUnitFromColor(this._originalColor, this.cssColor4);
     return colorObj.toString();
   },
 
diff --git a/devtools/client/themes/markup.css b/devtools/client/themes/markup.css
index 4b4cfd031..0569b7ce7 100644
--- a/devtools/client/themes/markup.css
+++ b/devtools/client/themes/markup.css
@@ -197,6 +197,22 @@ ul.children + .tag-line::before {
   display: inline;
 }
 
+.expandable.collapsed .close::before {
+  /* Display an ellipsis character in collapsed nodes that can be expanded. */
+  content: "\2026";
+  display: inline-block;
+  width: 12px;
+  height: 8px;
+  margin: 0 2px;
+  line-height: 3px;
+  color: var(--theme-body-color-inactive);
+  border-radius: 3px;
+  border-style: solid;
+  border-width: 1px;
+  text-align: center;
+  vertical-align: middle;
+}
+
 /* Hide HTML void elements (img, hr, br, …) closing tag when the element is not
  * expanded (it can be if it has pseudo-elements attached) */
 .child.collapsed > .tag-line .void-element .close {
@@ -318,7 +334,8 @@ ul.children + .tag-line::before {
 .theme-selected ~ .editor .theme-fg-color4,
 .theme-selected ~ .editor .theme-fg-color5,
 .theme-selected ~ .editor .theme-fg-color6,
-.theme-selected ~ .editor .theme-fg-color7 {
+.theme-selected ~ .editor .theme-fg-color7,
+.theme-selected ~ .editor .close::before {
   color: var(--theme-selection-color);
 }
 
diff --git a/devtools/server/actors/css-properties.js b/devtools/server/actors/css-properties.js
index d24c133d4..b22d8005f 100644
--- a/devtools/server/actors/css-properties.js
+++ b/devtools/server/actors/css-properties.js
@@ -31,8 +31,12 @@ exports.CssPropertiesActor = ActorClassWithSpec(cssPropertiesSpec, {
   getCSSDatabase() {
     const properties = generateCssProperties();
     const pseudoElements = DOMUtils.getCSSPseudoElementNames();
+    const supportedFeature = {
+      // checking for css-color-4 color function support.
+      "css-color-4-color-function": DOMUtils.isValidCSSColor("rgb(1 1 1 / 100%)"),
+    };
 
-    return { properties, pseudoElements };
+    return { properties, pseudoElements, supportedFeature };
   }
 });
 
diff --git a/devtools/server/actors/inspector.js b/devtools/server/actors/inspector.js
index 20a227a40..883809b6c 100644
--- a/devtools/server/actors/inspector.js
+++ b/devtools/server/actors/inspector.js
@@ -626,6 +626,18 @@ var NodeActor = exports.NodeActor = protocol.ActorClassWithSpec(nodeSpec, {
   },
 
   /**
+   * Get the full CSS path for this node.
+   *
+   * @return {String} A CSS selector with a part for the node and each of its ancestors.
+   */
+  getCssPath: function () {
+    if (Cu.isDeadWrapper(this.rawNode)) {
+      return "";
+    }
+    return CssLogic.getCssPath(this.rawNode);
+  },
+
+  /**
    * Scroll the selected node into view.
    */
   scrollIntoView: function () {
diff --git a/devtools/server/actors/root.js b/devtools/server/actors/root.js
index b6f8c0ee4..a5df148c2 100644
--- a/devtools/server/actors/root.js
+++ b/devtools/server/actors/root.js
@@ -145,6 +145,8 @@ RootActor.prototype = {
     addNewRule: true,
     // Whether the dom node actor implements the getUniqueSelector method
     getUniqueSelector: true,
+    // Whether the dom node actor implements the getCssPath method
+    getCssPath: true,
     // Whether the director scripts are supported
     directorScripts: true,
     // Whether the debugger server supports
diff --git a/devtools/server/css-logic.js b/devtools/server/css-logic.js
index f632871e1..c4a073635 100644
--- a/devtools/server/css-logic.js
+++ b/devtools/server/css-logic.js
@@ -793,6 +793,55 @@ CssLogic.findCssSelector = function (ele) {
 };
 
 /**
+ * Get the full CSS path for a given element.
+ * @returns a string that can be used as a CSS selector for the element. It might not
+ * match the element uniquely. It does however, represent the full path from the root
+ * node to the element.
+ */
+CssLogic.getCssPath = function (ele) {
+  ele = getRootBindingParent(ele);
+  const document = ele.ownerDocument;
+  if (!document || !document.contains(ele)) {
+    throw new Error("getCssPath received element not inside document");
+  }
+
+  const getElementSelector = element => {
+    if (!element.localName) {
+      return "";
+    }
+
+    let label = element.nodeName == element.nodeName.toUpperCase()
+                ? element.localName.toLowerCase()
+                : element.localName;
+
+    if (element.id) {
+      label += "#" + element.id;
+    }
+
+    if (element.classList) {
+      for (let cl of element.classList) {
+        label += "." + cl;
+      }
+    }
+
+    return label;
+  };
+
+  let paths = [];
+
+  while (ele) {
+    if (!ele || ele.nodeType !== Node.ELEMENT_NODE) {
+      break;
+    }
+
+    paths.splice(0, 0, getElementSelector(ele));
+    ele = ele.parentNode;
+  }
+
+  return paths.length ? paths.join(" ") : "";
+}
+
+/**
  * A safe way to access cached bits of information about a stylesheet.
  *
  * @constructor
diff --git a/devtools/shared/css/color.js b/devtools/shared/css/color.js
index b354043d7..98ddeff19 100644
--- a/devtools/shared/css/color.js
+++ b/devtools/shared/css/color.js
@@ -28,6 +28,10 @@ const SPECIALVALUES = new Set([
  * Usage:
  *   let {colorUtils} = require("devtools/shared/css/color");
  *   let color = new colorUtils.CssColor("red");
+ *   // In order to support css-color-4 color function, pass true to the
+ *   // second argument.
+ *   // e.g.
+ *   //   let color = new colorUtils.CssColor("red", true);
  *
  *   color.authored === "red"
  *   color.hasAlpha === false
@@ -58,8 +62,9 @@ const SPECIALVALUES = new Set([
  *   Valid values for COLOR_UNIT_PREF are contained in CssColor.COLORUNIT.
  */
 
-function CssColor(colorValue) {
+function CssColor(colorValue, supportsCssColor4ColorFunction = false) {
   this.newColor(colorValue);
+  this.cssColor4 = supportsCssColor4ColorFunction;
 }
 
 module.exports.colorUtils = {
@@ -92,6 +97,9 @@ CssColor.prototype = {
   // A lower-cased copy of |authored|.
   lowerCased: null,
 
+  // Whether the value should be parsed using css-color-4 rules.
+  cssColor4: false,
+
   _setColorUnitUppercase: function (color) {
     // Specifically exclude the case where the color is
     // case-insensitive.  This makes it so that "#000" isn't
@@ -136,7 +144,7 @@ CssColor.prototype = {
   },
 
   get valid() {
-    return isValidCSSColor(this.authored);
+    return isValidCSSColor(this.authored, this.cssColor4);
   },
 
   /**
@@ -393,7 +401,7 @@ CssColor.prototype = {
    * appropriate.
    */
   _getRGBATuple: function () {
-    let tuple = colorToRGBA(this.authored);
+    let tuple = colorToRGBA(this.authored, this.cssColor4);
 
     tuple.a = parseFloat(tuple.a.toFixed(1));
 
@@ -481,11 +489,13 @@ function roundTo(number, digits) {
  *         Color in the form of hex, hsl, hsla, rgb, rgba.
  * @param  {Number} alpha
  *         Alpha value for the color, between 0 and 1.
+ * @param  {Boolean} useCssColor4ColorFunction
+ *         use css-color-4 color function or not.
  * @return {String}
  *         Converted color with `alpha` value in rgba form.
  */
-function setAlpha(colorValue, alpha) {
-  let color = new CssColor(colorValue);
+function setAlpha(colorValue, alpha, useCssColor4ColorFunction = false) {
+  let color = new CssColor(colorValue, useCssColor4ColorFunction);
 
   // Throw if the color supplied is not valid.
   if (!color.valid) {
@@ -1049,12 +1059,11 @@ function parseOldStyleRgb(lexer, hasAlpha) {
  * color's components.  Any valid CSS color form can be passed in.
  *
  * @param {String} name the color
- * @param {Boolean} oldColorFunctionSyntax use old color function syntax or the
- *        css-color-4 syntax
+ * @param {Boolean} useCssColor4ColorFunction use css-color-4 color function or not.
  * @return {Object} an object of the form {r, g, b, a}; or null if the
  *         name was not a valid color
  */
-function colorToRGBA(name, oldColorFunctionSyntax = true) {
+function colorToRGBA(name, useCssColor4ColorFunction = false) {
   name = name.trim().toLowerCase();
 
   if (name in cssColors) {
@@ -1089,7 +1098,7 @@ function colorToRGBA(name, oldColorFunctionSyntax = true) {
   let hsl = func.text === "hsl" || func.text === "hsla";
 
   let vals;
-  if (oldColorFunctionSyntax) {
+  if (!useCssColor4ColorFunction) {
     let hasAlpha = (func.text === "rgba" || func.text === "hsla");
     vals = hsl ? parseOldStyleHsl(lexer, hasAlpha) : parseOldStyleRgb(lexer, hasAlpha);
   } else {
@@ -1110,8 +1119,9 @@ function colorToRGBA(name, oldColorFunctionSyntax = true) {
  * Check whether a string names a valid CSS color.
  *
  * @param {String} name The string to check
+ * @param {Boolean} useCssColor4ColorFunction use css-color-4 color function or not.
  * @return {Boolean} True if the string is a CSS color name.
  */
-function isValidCSSColor(name) {
-  return colorToRGBA(name) !== null;
+function isValidCSSColor(name, useCssColor4ColorFunction = false) {
+  return colorToRGBA(name, useCssColor4ColorFunction) !== null;
 }
diff --git a/devtools/shared/fronts/css-properties.js b/devtools/shared/fronts/css-properties.js
index 9b3172a22..d61bb4b07 100644
--- a/devtools/shared/fronts/css-properties.js
+++ b/devtools/shared/fronts/css-properties.js
@@ -47,6 +47,20 @@ const CssPropertiesFront = FrontClassWithSpec(cssPropertiesSpec, {
 });
 
 /**
+ * Query the feature supporting status in the featureSet.
+ *
+ * @param {Hashmap} featureSet the feature set hashmap
+ * @param {String} feature the feature name string
+ * @return {Boolean} has the feature or not
+ */
+function hasFeature(featureSet, feature) {
+  if (feature in featureSet) {
+    return featureSet[feature];
+  }
+  return false;
+}
+
+/**
  * Ask questions to a CSS database. This class does not care how the database
  * gets loaded in, only the questions that you can ask to it.
  * Prototype functions are bound to 'this' so they can be passed around as helper
@@ -62,10 +76,16 @@ function CssProperties(db) {
   this.properties = db.properties;
   this.pseudoElements = db.pseudoElements;
 
+  // supported feature
+  this.cssColor4ColorFunction = hasFeature(db.supportedFeature,
+                                           "css-color-4-color-function");
+
   this.isKnown = this.isKnown.bind(this);
   this.isInherited = this.isInherited.bind(this);
   this.supportsType = this.supportsType.bind(this);
   this.isValidOnClient = this.isValidOnClient.bind(this);
+  this.supportsCssColor4ColorFunction =
+    this.supportsCssColor4ColorFunction.bind(this);
 
   // A weakly held dummy HTMLDivElement to test CSS properties on the client.
   this._dummyElements = new WeakMap();
@@ -181,6 +201,15 @@ CssProperties.prototype = {
     }
     return [];
   },
+
+  /**
+   * Checking for the css-color-4 color function support.
+   *
+   * @return {Boolean} Return true if the server supports css-color-4 color function.
+   */
+  supportsCssColor4ColorFunction() {
+    return this.cssColor4ColorFunction;
+  },
 };
 
 /**
@@ -292,6 +321,11 @@ function normalizeCssData(db) {
 
   reattachCssColorValues(db);
 
+  // If there is no supportedFeature in db, create an empty one.
+  if (!db.supportedFeature) {
+    db.supportedFeature = {};
+  }
+
   return db;
 }
 
diff --git a/devtools/shared/gcli/source/lib/gcli/commands/commands.js b/devtools/shared/gcli/source/lib/gcli/commands/commands.js
index 67793b2dc..0af4be620 100644
--- a/devtools/shared/gcli/source/lib/gcli/commands/commands.js
+++ b/devtools/shared/gcli/source/lib/gcli/commands/commands.js
@@ -335,10 +335,10 @@ Parameter.prototype.toJson = function() {
   };
 
   // Values do not need to be serializable, so we don't try. For the client
-  // side (which doesn't do any executing) we don't actually care what the
-  // default value is, just that it exists
+  // side (which doesn't do any executing) we only care whether default value is
+  // undefined, null, or something else.
   if (this.paramSpec.defaultValue !== undefined) {
-    json.defaultValue = {};
+    json.defaultValue = (this.paramSpec.defaultValue === null) ? null : {};
   }
   if (this.paramSpec.description != null) {
     json.description = this.paramSpec.description;
diff --git a/devtools/shared/gcli/source/lib/gcli/commands/help.js b/devtools/shared/gcli/source/lib/gcli/commands/help.js
index 317f80240..7d1cc9087 100644
--- a/devtools/shared/gcli/source/lib/gcli/commands/help.js
+++ b/devtools/shared/gcli/source/lib/gcli/commands/help.js
@@ -69,7 +69,7 @@ function getHelpManData(commandData, context) {
       }
       else {
         // We need defaultText to work the text version of defaultValue
-        input = l10n.lookupFormat('helpManOptional');
+        input = l10n.lookup('helpManOptional');
         /*
         var val = param.type.stringify(param.defaultValue);
         input = Promise.resolve(val).then(function(defaultValue) {
diff --git a/devtools/shared/specs/node.js b/devtools/shared/specs/node.js
index ea3d1b264..022d7f1ac 100644
--- a/devtools/shared/specs/node.js
+++ b/devtools/shared/specs/node.js
@@ -37,6 +37,12 @@ const nodeSpec = generateActorSpec({
         value: RetVal("string")
       }
     },
+    getCssPath: {
+      request: {},
+      response: {
+        value: RetVal("string")
+      }
+    },
     scrollIntoView: {
       request: {},
       response: {}
diff --git a/devtools/shared/tests/mochitest/chrome.ini b/devtools/shared/tests/mochitest/chrome.ini
index 85ece7c48..3e4e028d1 100644
--- a/devtools/shared/tests/mochitest/chrome.ini
+++ b/devtools/shared/tests/mochitest/chrome.ini
@@ -2,6 +2,7 @@
 tags = devtools
 skip-if = os == 'android'
 
-[test_eventemitter_basic.html]
+[test_css-logic-getCssPath.html]
 [test_devtools_extensions.html]
+[test_eventemitter_basic.html]
 skip-if = os == 'linux' && debug # Bug 1205739
diff --git a/devtools/shared/tests/mochitest/test_css-logic-getCssPath.html b/devtools/shared/tests/mochitest/test_css-logic-getCssPath.html
new file mode 100644
index 000000000..2c444308a
--- /dev/null
+++ b/devtools/shared/tests/mochitest/test_css-logic-getCssPath.html
@@ -0,0 +1,121 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1323700
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test for Bug 1323700</title>
+
+  <script type="application/javascript" src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css">
+  <script type="application/javascript;version=1.8">
+const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
+
+let { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
+const CssLogic = require("devtools/shared/inspector/css-logic");
+
+var _tests = [];
+function addTest(test) {
+  _tests.push(test);
+}
+
+function runNextTest() {
+  if (_tests.length == 0) {
+    SimpleTest.finish()
+    return;
+  }
+  _tests.shift()();
+}
+
+window.onload = function() {
+  SimpleTest.waitForExplicitFinish();
+  runNextTest();
+}
+
+addTest(function getCssPathForUnattachedElement() {
+  var unattached = document.createElement("div");
+  unattached.id = "unattached";
+  try {
+    CssLogic.getCssPath(unattached);
+    ok(false, "Unattached node did not throw")
+  } catch(e) {
+    ok(e, "Unattached node throws an exception");
+  }
+
+  var unattachedChild = document.createElement("div");
+  unattached.appendChild(unattachedChild);
+  try {
+    CssLogic.getCssPath(unattachedChild);
+    ok(false, "Unattached child node did not throw")
+  } catch(e) {
+    ok(e, "Unattached child node throws an exception");
+  }
+
+  var unattachedBody = document.createElement("body");
+  try {
+    CssLogic.getCssPath(unattachedBody);
+    ok(false, "Unattached body node did not throw")
+  } catch(e) {
+    ok(e, "Unattached body node throws an exception");
+  }
+
+  runNextTest();
+});
+
+addTest(function cssPathHasOneStepForEachAncestor() {
+  for (let el of [...document.querySelectorAll('*')]) {
+    let splitPath = CssLogic.getCssPath(el).split(" ");
+
+    let expectedNbOfParts = 0;
+    var parent = el.parentNode;
+    while (parent) {
+      expectedNbOfParts ++;
+      parent = parent.parentNode;
+    }
+
+    is(splitPath.length, expectedNbOfParts, "There are enough parts in the full path");
+  }
+
+  runNextTest();
+});
+
+addTest(function getCssPath() {
+  let data = [{
+    selector: "#id",
+    path: "html body div div div.class div#id"
+  }, {
+    selector: "html",
+    path: "html"
+  }, {
+    selector: "body",
+    path: "html body"
+  }, {
+    selector: ".c1.c2.c3",
+    path: "html body span.c1.c2.c3"
+  }, {
+    selector: "#i",
+    path: "html body span#i.c1.c2"
+  }];
+
+  for (let {selector, path} of data) {
+    let node = document.querySelector(selector);
+    is (CssLogic.getCssPath(node), path, `Full css path is correct for ${selector}`);
+  }
+
+  runNextTest();
+});
+  </script>
+</head>
+<body>
+  <div>
+    <div>
+      <div class="class">
+        <div id="id"></div>
+      </div>
+    </div>
+  </div>
+  <span class="c1 c2 c3"></span>
+  <span id="i" class="c1 c2"></span>
+</body>
+</html>