[Slimming Paint] Paint the inspector overlay with GraphicsLayer DisplayList.

Source/web/PageOverlayList.cpp

 /*
  * 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.
  *
@@ skipping 96 matching lines @@
 }
 
 void PageOverlayList::update()
 {
     for (size_t i = 0; i < m_pageOverlays.size(); ++i)
         m_pageOverlays[i]->update();
 }
 
 void PageOverlayList::paintWebFrame(GraphicsContext& gc)
 {
+    // If accelerated compositing is active, page overlays are painted through
+    // their corresponding GraphicsLayer.
+    ASSERT(!m_viewImpl->isAcceleratedCompositingActive());
     for (size_t i = 0; i < m_pageOverlays.size(); ++i)
         m_pageOverlays[i]->paintWebFrame(gc);
 }
 
 size_t PageOverlayList::find(WebPageOverlay* overlay)
 {
     for (size_t i = 0; i < m_pageOverlays.size(); ++i) {
         if (m_pageOverlays[i]->overlay() == overlay)
             return i;
     }
     return WTF::kNotFound;
 }
 
 size_t PageOverlayList::findGraphicsLayer(GraphicsLayer* layer)
 {
     for (size_t i = 0; i < m_pageOverlays.size(); ++i) {
         if (m_pageOverlays[i]->graphicsLayer() == layer)
             return i;
     }
     return WTF::kNotFound;
 }
 
+GraphicsLayer* PageOverlayList::graphicsLayerForTesting() const
+{
+    if (m_pageOverlays.isEmpty())
+        return nullptr;
+    return m_pageOverlays[0]->graphicsLayer();
+}
+
 } // namespace blink