Make profiling lock global rather than per Target

Source/devtools/front_end/sdk/WorkerTargetManager.js

Index: Source/devtools/front_end/sdk/WorkerTargetManager.js
diff --git a/Source/devtools/front_end/sdk/WorkerTargetManager.js b/Source/devtools/front_end/sdk/WorkerTargetManager.js
index 698087fee367118b1467891c4b9ad58bfa7a3c89..8bd0622bf868bae23aeffbdf1302d2eb7e65dc44 100644
--- a/Source/devtools/front_end/sdk/WorkerTargetManager.js
+++ b/Source/devtools/front_end/sdk/WorkerTargetManager.js
@@ -13,14 +13,14 @@ WebInspector.WorkerTargetManager = function(mainTarget, targetManager)
     this._mainTarget = mainTarget;
     this._targetManager = targetManager;
     mainTarget.workerManager.addEventListener(WebInspector.WorkerManager.Events.WorkerAdded, this._onWorkerAdded, this);
-    mainTarget.profilingLock.addEventListener(WebInspector.Lock.Events.StateChanged, this._onProfilingStateChanged, this);
+    WebInspector.profilingLock.addEventListener(WebInspector.Lock.Events.StateChanged, this._onProfilingStateChanged, this);
     this._onProfilingStateChanged();
 }
 
 WebInspector.WorkerTargetManager.prototype = {
     _onProfilingStateChanged: function()
     {
-        var acquired = this._mainTarget.profilingLock.isAcquired();
+        var acquired = WebInspector.profilingLock.isAcquired();
         this._mainTarget.workerAgent().setAutoconnectToWorkers(!acquired);
     },