DevTools: get rid of the global capabilities set.

Source/devtools/front_end/sources/SourcesPanel.js

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 107 matching lines @@
     this.sidebarPanes.callstack = new WebInspector.CallStackSidebarPane();
     this.sidebarPanes.callstack.addEventListener(WebInspector.CallStackSidebarPane.Events.CallFrameSelected, this._callFrameSelectedInSidebar.bind(this));
     this.sidebarPanes.callstack.registerShortcuts(this.registerShortcuts.bind(this));
 
     this.sidebarPanes.scopechain = new WebInspector.ScopeChainSidebarPane();
     this.sidebarPanes.jsBreakpoints = new WebInspector.JavaScriptBreakpointsSidebarPane(WebInspector.breakpointManager, this.showUISourceCode.bind(this));
     this.sidebarPanes.domBreakpoints = WebInspector.domBreakpointsSidebarPane.createProxy(this);
     this.sidebarPanes.xhrBreakpoints = new WebInspector.XHRBreakpointsSidebarPane();
     this.sidebarPanes.eventListenerBreakpoints = new WebInspector.EventListenerBreakpointsSidebarPane();
 
-    if (Capabilities.isMainFrontend)
+    if (!WebInspector.isWorkerFrontend())
         this.sidebarPanes.workerList = new WebInspector.WorkersSidebarPane();
 
     this._extensionSidebarPanes = [];
     this._installDebuggerSidebarController();
 
     WebInspector.dockController.addEventListener(WebInspector.DockController.Events.DockSideChanged, this._dockSideChanged.bind(this));
     WebInspector.settings.splitVerticallyWhenDockedToRight.addChangeListener(this._dockSideChanged.bind(this));
     this._dockSideChanged();
 
     this._updateDebuggerButtons();
@@ skipping 1335 matching lines @@
      */
     handleAction: function()
     {
         var panel = /** @type {?WebInspector.SourcesPanel} */ (WebInspector.inspectorView.showPanel("sources"));
         if (!panel)
             return false;
         panel.togglePause();
         return true;
     }
 }