[DevTools] Use device metrics emulation implemented in content.

Source/core/platform/ScrollbarThemeMacCommon.mm

 /*
  * Copyright (C) 2008, 2011 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 14 matching lines @@
 
 #include "config.h"
 #include "core/platform/ScrollbarThemeMacCommon.h"
 
 #include <Carbon/Carbon.h>
 #include "core/page/FrameView.h"
 #include "core/platform/PlatformMouseEvent.h"
 #include "core/platform/ScrollView.h"
 #include "core/platform/ScrollbarThemeMacNonOverlayAPI.h"
 #include "core/platform/ScrollbarThemeMacOverlayAPI.h"
+#include "core/platform/ScrollbarThemeOverlay.h"
 #include "core/platform/graphics/Gradient.h"
 #include "core/platform/graphics/GraphicsContext.h"
 #include "core/platform/graphics/GraphicsContextStateSaver.h"
 #include "core/platform/graphics/GraphicsLayer.h"
 #include "core/platform/graphics/ImageBuffer.h"
 #include "core/platform/graphics/mac/ColorMac.h"
 #include "core/platform/mac/LocalCurrentGraphicsContext.h"
 #include "core/platform/mac/NSScrollerImpDetails.h"
 #include "core/platform/mac/ScrollAnimatorMac.h"
 #include "public/platform/mac/WebThemeEngine.h"
@@ skipping 76 matching lines @@
 @end
 
 namespace WebCore {
 
 static float gInitialButtonDelay = 0.5f;
 static float gAutoscrollButtonDelay = 0.05f;
 static bool gJumpOnTrackClick = false;
 
 ScrollbarTheme* ScrollbarTheme::nativeTheme()
 {
+    if (RuntimeEnabledFeatures::overlayScrollbarsEnabled()) {

[pfeldman, 2013/09/19 12:46:05]

Lets land this separately.

[dgozman, 2013/09/19 13:59:38]

Done.

+        DEFINE_STATIC_LOCAL(ScrollbarThemeOverlay, theme, (7, 0, ScrollbarThemeOverlay::AllowHitTest));
+        return &theme;
+    }
+
     if (isScrollbarOverlayAPIAvailable()) {
         DEFINE_STATIC_LOCAL(ScrollbarThemeMacOverlayAPI, theme, ());
         return &theme;
     } else {
         DEFINE_STATIC_LOCAL(ScrollbarThemeMacNonOverlayAPI, theme, ());
         return &theme;
     }
     return NULL;
 }
 
@@ skipping 278 matching lines @@
         case ForwardButtonEndPart:
             return kThemeBottomOutsideArrowPressed;
         case ThumbPart:
             return kThemeThumbPressed;
         default:
             return 0;
     }
 }
 
 } // namespace WebCore