DevTools: [CSS] promisify CSS domain

Source/devtools/front_end/elements/StylesSidebarPane.js

Index: Source/devtools/front_end/elements/StylesSidebarPane.js
diff --git a/Source/devtools/front_end/elements/StylesSidebarPane.js b/Source/devtools/front_end/elements/StylesSidebarPane.js
index 28c3da877d3460293b6a8940f7b9abd82217f034..64edcdf6327820994fffd57389868707fabec73a 100644
--- a/Source/devtools/front_end/elements/StylesSidebarPane.js
+++ b/Source/devtools/front_end/elements/StylesSidebarPane.js
@@ -1549,28 +1549,22 @@ WebInspector.StylePropertiesSection.prototype = {
             newContent = newContent.trim();
 
         /**
-         * @param {!WebInspector.CSSMedia} newMedia
+         * @param {?WebInspector.CSSMedia} newMedia
          * @this {WebInspector.StylePropertiesSection}
          */
-        function successCallback(newMedia)
-        {
-            this._parentPane._styleSheetMediaEdited(media, newMedia);
-            this._parentPane._refreshUpdate(this);
-            finishOperation.call(this);
-        }
-
-        /**
-         * @this {WebInspector.StylePropertiesSection}
-         */
-        function finishOperation()
+        function userCallback(newMedia)
         {
+            if (newMedia) {
+                this._parentPane._styleSheetMediaEdited(media, newMedia);
+                this._parentPane._refreshUpdate(this);
+            }
             delete this._parentPane._userOperation;
             this._editingMediaTextCommittedForTest();
         }
 
         // This gets deleted in finishOperation(), which is called both on success and failure.
         this._parentPane._userOperation = true;
-        this._parentPane._cssModel.setMediaText(media, newContent, successCallback.bind(this), finishOperation.bind(this));
+        this._parentPane._cssModel.setMediaText(media, newContent, userCallback.bind(this));
     },
 
     _editingMediaTextCommittedForTest: function() { },
@@ -1700,38 +1694,31 @@ WebInspector.StylePropertiesSection.prototype = {
         }
 
         /**
-         * @param {!WebInspector.CSSRule} newRule
+         * @param {?WebInspector.CSSRule} newRule
          * @this {WebInspector.StylePropertiesSection}
          */
-        function successCallback(newRule)
+        function finishCallback(newRule)
         {
-            var doesAffectSelectedNode = newRule.matchingSelectors.length > 0;
-            this.element.classList.toggle("no-affect", !doesAffectSelectedNode);
-
-            var oldSelectorRange = this.rule().selectorRange;
-            this.styleRule.updateRule(newRule);
+            if (newRule) {
+                var doesAffectSelectedNode = newRule.matchingSelectors.length > 0;
+                this.element.classList.toggle("no-affect", !doesAffectSelectedNode);
 
-            this._parentPane._refreshUpdate(this);
-            this._parentPane._styleSheetRuleEdited(newRule, oldSelectorRange, newRule.selectorRange);
+                var oldSelectorRange = this.rule().selectorRange;
+                this.styleRule.updateRule(newRule);
 
-            finishOperationAndMoveEditor.call(this, moveDirection);
-        }
+                this._parentPane._refreshUpdate(this);
+                this._parentPane._styleSheetRuleEdited(newRule, oldSelectorRange, newRule.selectorRange);
+            }
 
-        /**
-         * @param {string} direction
-         * @this {WebInspector.StylePropertiesSection}
-         */
-        function finishOperationAndMoveEditor(direction)
-        {
             delete this._parentPane._userOperation;
-            this._moveEditorFromSelector(direction);
+            this._moveEditorFromSelector(moveDirection);
             this._editingSelectorCommittedForTest();
         }
 
         // This gets deleted in finishOperationAndMoveEditor(), which is called both on success and failure.
         this._parentPane._userOperation = true;
         var selectedNode = this._parentPane.node();
-        this._parentPane._cssModel.setRuleSelector(this.rule(), selectedNode ? selectedNode.id : 0, newContent, successCallback.bind(this), finishOperationAndMoveEditor.bind(this, moveDirection));
+        this._parentPane._cssModel.setRuleSelector(this.rule(), selectedNode ? selectedNode.id : 0, newContent, finishCallback.bind(this));
     },
 
     _editingSelectorCommittedForTest: function() { },
@@ -1878,11 +1865,16 @@ WebInspector.BlankStylePropertiesSection.prototype = {
         }
 
         /**
-         * @param {!WebInspector.CSSRule} newRule
+         * @param {?WebInspector.CSSRule} newRule
          * @this {WebInspector.StylePropertiesSection}
          */
-        function successCallback(newRule)
+        function userCallback(newRule)
         {
+            if (!newRule) {
+                this.editingSelectorCancelled();
+                this._editingSelectorCommittedForTest();
+                return;
+            }
             var doesSelectorAffectSelectedNode = newRule.matchingSelectors.length > 0;
             this._makeNormal(newRule);
 
@@ -1906,22 +1898,13 @@ WebInspector.BlankStylePropertiesSection.prototype = {
             this._editingSelectorCommittedForTest();
         }
 
-        /**
-         * @this {WebInspector.StylePropertiesSection}
-         */
-        function failureCallback()
-        {
-            this.editingSelectorCancelled();
-            this._editingSelectorCommittedForTest();
-        }
-
         if (newContent)
             newContent = newContent.trim();
         this._parentPane._userOperation = true;
 
         var cssModel = this._parentPane._cssModel;
         var ruleText = this._rulePrefix() + newContent + " {}";
-        cssModel.addRule(this._styleSheetId, this._parentPane.node(), ruleText, this._ruleLocation, successCallback.bind(this), failureCallback.bind(this));
+        cssModel.addRule(this._styleSheetId, this._parentPane.node(), ruleText, this._ruleLocation, userCallback.bind(this));
     },
 
     editingSelectorCancelled: function()