DevTools: [CSS] promisify CSSStyleModel fetching methods

Source/devtools/front_end/elements/MetricsSidebarPane.js

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 51 matching lines @@
         /**
          * @param {?WebInspector.CSSStyleDeclaration} style
          * @this {WebInspector.MetricsSidebarPane}
          */
         function callback(style)
         {
             if (!style || this.node() !== node)
                 return;
             this._updateMetrics(style);
         }
-        cssModel.getComputedStyleAsync(node.id, callback.bind(this));
-
         /**
          * @param {?WebInspector.CSSStyleModel.InlineStyleResult} inlineStyleResult
          * @this {WebInspector.MetricsSidebarPane}
          */
         function inlineStyleCallback(inlineStyleResult)
         {
             if (inlineStyleResult && this.node() === node)
                 this.inlineStyle = inlineStyleResult.inlineStyle;
-            finishedCallback();
         }
-        cssModel.getInlineStylesAsync(node.id, inlineStyleCallback.bind(this));
+
+        var promises = [
+            cssModel.computedStylePromise(node.id).then(callback.bind(this)),
+            cssModel.inlineStylesPromise(node.id).then(inlineStyleCallback.bind(this))
+        ];
+        Promise.all(promises)
+            .then(finishedCallback.bind(null, undefined))
+            .catch(/** @type {function()} */(finishedCallback));
     },
 
     /**
      * @override
      */
     onDOMModelChanged: function()
     {
         this.update();
     },
 
@@ skipping 361 matching lines @@
     },
 
     editingCommitted: function(element, userInput, previousContent, context)
     {
         this.editingEnded(element, context);
         this._applyUserInput(element, userInput, previousContent, context, true);
     },
 
     __proto__: WebInspector.ElementsSidebarPane.prototype
 }