Make profiling lock global rather than per Target

Source/devtools/front_end/profiler/CanvasProfileView.js

 /*
  * Copyright (C) 2013 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 682 matching lines @@
         } else {
             this._recording = true;
             this._startFrameCapturing();
         }
         return this._recording;
     },
 
     _runSingleFrameCapturing: function()
     {
         var frameId = this._selectedFrameId();
-        this._target.profilingLock.acquire();
+        WebInspector.profilingLock.acquire();
         CanvasAgent.captureFrame(frameId, this._didStartCapturingFrame.bind(this, frameId));
-        this._target.profilingLock.release();
+        WebInspector.profilingLock.release();
     },
 
     _startFrameCapturing: function()
     {
         var frameId = this._selectedFrameId();
-        this._target.profilingLock.acquire();
+        WebInspector.profilingLock.acquire();
         CanvasAgent.startCapturing(frameId, this._didStartCapturingFrame.bind(this, frameId));
     },
 
     _stopFrameCapturing: function()
     {
         if (!this._lastProfileHeader) {
-            this._target.profilingLock.release();
+            WebInspector.profilingLock.release();
             return;
         }
         var profileHeader = this._lastProfileHeader;
         var traceLogId = profileHeader.traceLogId();
         this._lastProfileHeader = null;
         function didStopCapturing()
         {
             profileHeader._updateCapturingStatus();
         }
         CanvasAgent.stopCapturing(traceLogId, didStopCapturing);
-        this._target.profilingLock.release();
+        WebInspector.profilingLock.release();
     },
 
     /**
      * @param {string|undefined} frameId
      * @param {?Protocol.Error} error
      * @param {!CanvasAgent.TraceLogId} traceLogId
      */
     _didStartCapturingFrame: function(frameId, error, traceLogId)
     {
         if (error || this._lastProfileHeader && this._lastProfileHeader.traceLogId() === traceLogId)
@@ skipping 540 matching lines @@
     },
 
     clearResourceStates: function()
     {
         this._currentResourceStates = {};
         this.dispatchEventToListeners(WebInspector.CanvasTraceLogPlayerProxy.Events.CanvasReplayStateChanged);
     },
 
     __proto__: WebInspector.Object.prototype
 }