DevTools: [CSS] promisify CSSStyleModel fetching methods

Source/devtools/front_end/elements/SharedSidebarModel.js

Index: Source/devtools/front_end/elements/SharedSidebarModel.js
diff --git a/Source/devtools/front_end/elements/SharedSidebarModel.js b/Source/devtools/front_end/elements/SharedSidebarModel.js
index 43e1591ab07fef854f58eb8803f9babb2a3d431d..e322a41e32c9e1f941124b48ea789bfcd1906440 100644
--- a/Source/devtools/front_end/elements/SharedSidebarModel.js
+++ b/Source/devtools/front_end/elements/SharedSidebarModel.js
@@ -107,21 +107,12 @@ WebInspector.SharedSidebarModel.prototype = {
             return Promise.resolve(/** @type {?WebInspector.SharedSidebarModel.ComputedStyle} */(null));
 
         if (!this._computedStylePromise)
-            this._computedStylePromise = new Promise(getComputedStyle.bind(null, elementNode)).then(verifyOutdated.bind(this, elementNode));
+            this._computedStylePromise = cssModel.computedStylePromise(elementNode.id).then(verifyOutdated.bind(this, elementNode));
 
         return this._computedStylePromise;
 
         /**
          * @param {!WebInspector.DOMNode} elementNode
-         * @param {function(?WebInspector.CSSStyleDeclaration)} resolve
-         */
-        function getComputedStyle(elementNode, resolve)
-        {
-            cssModel.getComputedStyleAsync(elementNode.id, resolve);
-        }
-
-        /**
-         * @param {!WebInspector.DOMNode} elementNode
          * @param {?WebInspector.CSSStyleDeclaration} style
          * @return {?WebInspector.SharedSidebarModel.ComputedStyle}
          * @this {WebInspector.SharedSidebarModel}