[SPv2] Introduce an option to output the GraphicsLayer tree as a flat layer list.

third_party/WebKit/Source/platform/graphics/GraphicsLayer.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. 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 297 matching lines @@
 
   void setContentsTo(WebLayer*);
   void setupContentsLayer(WebLayer*);
   void clearContentsLayerIfUnregistered();
   WebLayer* contentsLayerIfRegistered();
 
   typedef HashMap<int, int> RenderingContextMap;
   std::unique_ptr<JSONObject> layerTreeAsJSONInternal(
       LayerTreeFlags,
       RenderingContextMap&) const;
+  // Outputs the layer tree rooted at |this| as a JSON array, in paint order.
+  void layersAsJSONArray(LayerTreeFlags,
+                         RenderingContextMap&,
+                         JSONArray*) const;
+  std::unique_ptr<JSONObject> layerAsJSONInternal(LayerTreeFlags,
+                                                  RenderingContextMap&) const;
 
   sk_sp<SkPicture> capturePicture();
   void checkPaintUnderInvalidations(const SkPicture&);
 
   GraphicsLayerClient* m_client;
 
   // Offset from the owning layoutObject
   DoubleSize m_offsetFromLayoutObject;
 
   // Position is relative to the parent GraphicsLayer
@@ skipping 59 matching lines @@
 };
 
 }  // namespace blink
 
 #ifndef NDEBUG
 // Outside the blink namespace for ease of invocation from gdb.
 void PLATFORM_EXPORT showGraphicsLayerTree(const blink::GraphicsLayer*);
 #endif
 
 #endif  // GraphicsLayer_h