Make profiling lock global rather than per Target

Source/devtools/front_end/sdk/Target.js

 /*
  * Copyright 2014 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /**
  * @constructor
  * @extends {Protocol.Agents}
  * @param {string} name
@@ skipping 14 matching lines @@
     this._modelByConstructor = new Map();
 
     /** @type {!Object.<string, boolean>} */
     this._capabilities = {};
     this.pageAgent().canScreencast(this._initializeCapability.bind(this, WebInspector.Target.Capabilities.CanScreencast, null));
     if (WebInspector.experimentsSettings.timelinePowerProfiler.isEnabled())
         this.powerAgent().canProfilePower(this._initializeCapability.bind(this, WebInspector.Target.Capabilities.CanProfilePower, null));
     this.workerAgent().canInspectWorkers(this._initializeCapability.bind(this, WebInspector.Target.Capabilities.CanInspectWorkers, this._loadedWithCapabilities.bind(this, callback)));
     if (WebInspector.experimentsSettings.timelineOnTraceEvents.isEnabled())
         this.consoleAgent().setTracingBasedTimeline(true);
-
-    /** @type {!WebInspector.Lock} */
-    this.profilingLock = new WebInspector.Lock();
 }
 
 /**
  * @enum {string}
  */
 WebInspector.Target.Capabilities = {
     CanScreencast: "CanScreencast",
     HasTouchInputs: "HasTouchInputs",
     CanProfilePower: "CanProfilePower",
     CanInspectWorkers: "CanInspectWorkers"
@@ skipping 378 matching lines @@
     /**
      * @param {!WebInspector.Target} target
      */
     targetRemoved: function(target) { },
 }
 
 /**
  * @type {!WebInspector.TargetManager}
  */
 WebInspector.targetManager = new WebInspector.TargetManager();