Add effect node support in PaintArtifactCompositor for layer list mode [1/4]

third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PaintArtifactCompositor_h
 #define PaintArtifactCompositor_h
 
 #include "base/memory/ref_counted.h"
 #include "platform/PlatformExport.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/Vector.h"
 
 namespace cc {
 class Layer;
 }
 
 namespace gfx {
 class Transform;
+class Vector2dF;
 }
 
 namespace blink {
 
 class PaintArtifact;
 class WebLayer;
 struct PaintChunk;
 
 // Responsible for managing compositing in terms of a PaintArtifact.
 //
@@ skipping 16 matching lines @@
     cc::Layer* rootLayer() const { return m_rootLayer.get(); }
 
     // Wraps rootLayer(), so that it can be attached as a child of another
     // WebLayer.
     WebLayer* getWebLayer() const { return m_webLayer.get(); }
 
 private:
     class ContentLayerClientImpl;
 
     // Builds a leaf layer that represents a single paint chunk.
-    scoped_refptr<cc::Layer> layerForPaintChunk(const PaintArtifact&, const PaintChunk&, gfx::Transform);
+    // Note: cc::Layer API assumes the layer bounds to start at (0, 0) but the bounding box of
+    // a paint chunk does not necessarily start at (0, 0) and could even be negative. Internally
+    // the generated layer translates the paint chunk to align the bounding box to (0, 0) and
+    // return the actual origin of the paint chunk in output parameter layerOffset.
+    scoped_refptr<cc::Layer> layerForPaintChunk(const PaintArtifact&, const PaintChunk&, gfx::Vector2dF& layerOffset);
 
     scoped_refptr<cc::Layer> m_rootLayer;
     OwnPtr<WebLayer> m_webLayer;
     Vector<OwnPtr<ContentLayerClientImpl>> m_contentLayerClients;
 };
 
 } // namespace blink
 
 #endif // PaintArtifactCompositor_h