DevTools: promisify ContentProvider.requestContent and all its clients.

third_party/WebKit/Source/devtools/front_end/network/RequestResponseView.js

 /*
  * Copyright (C) 2011 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 101 matching lines @@
      * @override
      * @return {!WebInspector.ResourceType}
      */
     contentType: function()
     {
         return this._request.resourceType();
     },
 
     /**
      * @override
-     * @param {function(?string)} callback
+     * @return {!Promise<?string>}
      */
-    requestContent: function(callback)
+    requestContent: function()
     {
         /**
          * @param {?string} content
          * @this {WebInspector.RequestResponseView.ContentProvider}
          */
         function decodeContent(content)
         {
-            callback(this._request.contentEncoded ? window.atob(content || "") : content);
+            return this._request.contentEncoded ? window.atob(content || "") : content;
         }
 
-        this._request.requestContent(decodeContent.bind(this));
+        return this._request.requestContent()
+            .then(decodeContent.bind(this));
     },
 
     /**
      * @override
      * @param {string} query
      * @param {boolean} caseSensitive
      * @param {boolean} isRegex
      * @param {function(!Array.<!WebInspector.ContentProvider.SearchMatch>)} callback
      */
     searchInContent: function(query, caseSensitive, isRegex, callback)
     {
         this._request.searchInContent(query, caseSensitive, isRegex, callback);
     }
 }