DevTools: Promisify Profiler and HeapProfiler domains

third_party/WebKit/Source/devtools/front_end/protocol/InspectorBackend.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 610 matching lines @@
           for (var paramName of this._replyArgs[method] || [])
             argumentsArray.push(result[paramName]);
         }
         resolve(argumentsArray);
       }
       this._target._wrapCallbackAndSendMessageObject(this._domain, method, params, prepareArgsAndResolve.bind(this));
     }
 
     /**
      * @param {!Array<*>} args
+     * @return {?}
      */
     function runUserCallback(args) {
-      return userCallback ? userCallback.apply(null, args) : undefined;
+      return userCallback ? userCallback.apply(null, args) : !args[0] && args[1] || null;
     }
   }
 
   /**
    * @param {string} method
    * @param {?Object} request
    * @return {!Promise<!Object>}
    */
   _invoke(method, request) {
     return new Promise(fulfill => {
@@ skipping 85 matching lines @@
     if (Protocol.InspectorBackend.Options.dumpInspectorTimeStats)
       console.timeEnd(timingLabel);
   }
 };
 
 Protocol.InspectorBackend.Options = {
   dumpInspectorTimeStats: false,
   dumpInspectorProtocolMessages: false,
   suppressRequestErrors: false
 };