DevTools: check for canForceCompositingMode before trying to emulate device metrics.

Source/devtools/front_end/inspector.js

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2007 Matt Lilek (pewtermoose@gmail.com).
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * 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
@@ skipping 420 matching lines @@
 
     this.fileSystemWorkspaceProvider = new WebInspector.FileSystemWorkspaceProvider(this.isolatedFileSystemManager, this.workspace);
 
     this.networkWorkspaceProvider = new WebInspector.SimpleWorkspaceProvider(this.workspace, WebInspector.projectTypes.Network);
     new WebInspector.NetworkUISourceCodeProvider(this.networkWorkspaceProvider, this.workspace);
 
     this.breakpointManager = new WebInspector.BreakpointManager(WebInspector.settings.breakpoints, this.debuggerModel, this.workspace);
 
     this.scriptSnippetModel = new WebInspector.ScriptSnippetModel(this.workspace);
 
+    this.overridesSupport = new WebInspector.OverridesSupport();
+
     new WebInspector.DebuggerScriptMapping(this.workspace, this.networkWorkspaceProvider);
     this.liveEditSupport = new WebInspector.LiveEditSupport(this.workspace);
     new WebInspector.CSSStyleSheetMapping(this.cssModel, this.workspace, this.networkWorkspaceProvider);
     new WebInspector.PresentationConsoleMessageHelper(this.workspace);
 
     this._createGlobalStatusBarItems();
 
     WebInspector.startBatchUpdate();
     for (var i = 0; i < panelDescriptors.length; ++i)
         WebInspector.inspectorView.addPanel(panelDescriptors[i]);
@@ skipping 30 matching lines @@
     WebInspector.settings.continuousPainting = WebInspector.settings.createBackendSetting("continuousPainting", false, PageAgent.setContinuousPaintingEnabled.bind(PageAgent));
     WebInspector.settings.showFPSCounter = WebInspector.settings.createBackendSetting("showFPSCounter", false, PageAgent.setShowFPSCounter.bind(PageAgent));
     WebInspector.settings.showScrollBottleneckRects = WebInspector.settings.createBackendSetting("showScrollBottleneckRects", false, PageAgent.setShowScrollBottleneckRects.bind(PageAgent));
 
     WebInspector.settings.showMetricsRulers.addChangeListener(showRulersChanged);
     function showRulersChanged()
     {
         PageAgent.setShowViewportSizeOnResize(true, WebInspector.settings.showMetricsRulers.get());
     }
     showRulersChanged();
-    this.overridesSupport = new WebInspector.OverridesSupport();
 
     WebInspector.WorkerManager.loadCompleted();
     InspectorFrontendAPI.loadCompleted();
 
     if (Capabilities.canScreencast && WebInspector.settings.screencastEnabled.get())
         this._toggleScreencastButtonClicked(false);
 
     WebInspector.notifications.dispatchEventToListeners(WebInspector.Events.InspectorLoaded);
 }
 
@@ skipping 539 matching lines @@
 
 /**
  * @return {string}
  */
 WebInspector.getSelectionForegroundColor = function()
 {
     return InspectorFrontendHost.getSelectionForegroundColor();
 }
 
 window.DEBUG = true;