DevTools: promisify ContentProvider.requestContent and all its clients.

third_party/WebKit/Source/devtools/front_end/sdk/NetworkRequest.js

 /*
  * Copyright (C) 2012 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 915 matching lines @@
      * @override
      * @return {!WebInspector.ResourceType}
      */
     contentType: function()
     {
         return this._resourceType;
     },
 
     /**
      * @override
-     * @param {function(?string)} callback
+     * @return {!Promise<?string>}
      */
-    requestContent: function(callback)
+    requestContent: function()
     {
         // We do not support content retrieval for WebSockets at the moment.
         // Since WebSockets are potentially long-living, fail requests immediately
         // to prevent caller blocking until resource is marked as finished.
-        if (this._resourceType === WebInspector.resourceTypes.WebSocket) {
-            callback(null);
-            return;
-        }
-        if (typeof this._content !== "undefined") {
-            callback(this.content || null);
-            return;
-        }
+        if (this._resourceType === WebInspector.resourceTypes.WebSocket)
+            return Promise.resolve(/** @type {?string} */(null));
+        if (typeof this._content !== "undefined")
+            return Promise.resolve(/** @type {?string} */(this.content || null));
+        var callback;
+        var promise = new Promise(fulfill => callback = fulfill);
         this._pendingContentCallbacks.push(callback);
         if (this.finished)
             this._innerRequestContent();
+        return promise;
     },
 
     /**
      * @override
      * @param {string} query
      * @param {boolean} caseSensitive
      * @param {boolean} isRegex
      * @param {function(!Array.<!WebInspector.ContentProvider.SearchMatch>)} callback
      */
     searchInContent: function(query, caseSensitive, isRegex, callback)
@@ skipping 218 matching lines @@
         this.dispatchEventToListeners(WebInspector.NetworkRequest.Events.EventSourceMessageAdded, message);
     },
 
     replayXHR: function()
     {
         this.target().networkAgent().replayXHR(this.requestId);
     },
 
     __proto__: WebInspector.SDKObject.prototype
 }