Slimming Paint phase 2 compositing algorithm plumbing & skeleton display list API.

public/platform/WebContentLayerClient.h

 /*
  * 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 14 matching lines @@
 
 #ifndef WebContentLayerClient_h
 #define WebContentLayerClient_h
 
 #include "WebCanvas.h"
 #include "WebCommon.h"
 
 namespace blink {
 
 class WebDisplayItemList;
+class WebDisplayItemTransformTree;
+class WebDisplayList;
 struct WebRect;
 
 class BLINK_PLATFORM_EXPORT WebContentLayerClient {
 public:
     enum PaintingControlSetting {
         PaintDefaultBehavior,
         DisplayListConstructionDisabled,
         DisplayListCachingDisabled,
         DisplayListPaintingDisabled
     };
@@ skipping 17 matching lines @@
         WebDisplayItemList*,
         const WebRect& clip,
         PaintingControlSetting = PaintDefaultBehavior) = 0;
 
     // Returns an estimate of the current memory usage within this object,
     // excluding memory shared with painting artifacts (i.e.,
     // WebDisplayItemList). Should be invoked after paintContents, so that the
     // result includes data cached internally during painting.
     virtual size_t approximateUnsharedMemoryUsage() const { return 0; }
 
+    virtual const WebDisplayList* displayList() const { return 0; };
+
+    // This is only set on a root graphics layer. Alternatively, this could be set on the layer tree host.
+    virtual const WebDisplayItemTransformTree* transformTree() const { return 0; };
+
 protected:
     virtual ~WebContentLayerClient() { }
 };
 
 } // namespace blink
 
 #endif // WebContentLayerClient_h