DevTools: [CSS] promisify CSS domain

Source/devtools/front_end/timeline/TimelineModel.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 627 matching lines @@
         return Promise.all(this._targets.map(this._startProfilingOnTarget));
     },
 
     /**
      * @param {!WebInspector.Target} target
      * @return {!Promise}
      */
     _stopProfilingOnTarget: function(target)
     {
         /**
-         * @param {?{profile: !ProfilerAgent.CPUProfile}} value
+         * @param {?Protocol.Error} error
+         * @param {?ProfilerAgent.CPUProfile} profile
          * @return {?ProfilerAgent.CPUProfile}
          */
-        function extractProfile(value)
+        function extractProfile(error, profile)
         {
-            return value && value.profile;
+            return !error && profile ? profile : null;
         }
-        return target.profilerAgent().stop().then(extractProfile).then(this._addCpuProfile.bind(this, target.id()));
+        return target.profilerAgent().stop(extractProfile).then(this._addCpuProfile.bind(this, target.id()));

[alph, 2015/06/24 16:54:18]

what's that? why stop gets a callback as a parameters?

     },
 
     /**
      * @return {!Promise}
      */
     _stopProfilingOnAllTargets: function()
     {
         var targets = this._profiling ? this._targets : [];
         this._profiling = false;
         return Promise.all(targets.map(this._stopProfilingOnTarget, this));
@@ skipping 1417 matching lines @@
         /** @type {!Object.<string, !Array.<!WebInspector.InvalidationTrackingEvent>>} */
         this._invalidations = {};
         /** @type {!Object.<number, !Array.<!WebInspector.InvalidationTrackingEvent>>} */
         this._invalidationsByNodeId = {};
 
         this._lastRecalcStyle = undefined;
         this._lastPaintWithLayer = undefined;
         this._didPaint = false;
     }
 }