wip: not for commit (update twin relationship)

cc/layers/picture_layer_impl.h

 // Copyright 2012 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 CC_LAYERS_PICTURE_LAYER_IMPL_H_
 #define CC_LAYERS_PICTURE_LAYER_IMPL_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 161 matching lines @@
       float contents_scale,
       const gfx::Rect& rect,
       const Region& missing_region) const;
   gfx::Rect GetViewportForTilePriorityInContentSpace() const;
 
   void DoPostCommitInitializationIfNeeded() {
     if (needs_post_commit_initialization_)
       DoPostCommitInitialization();
   }
   void DoPostCommitInitialization();
+  void UpdateTwinRelationship();
 
   bool CanHaveTilings() const;
   bool CanHaveTilingWithScale(float contents_scale) const;
   void SanityCheckTilingState() const;
 
   bool ShouldAdjustRasterScaleDuringScaleAnimations() const;
 
   virtual void GetDebugBorderProperties(
       SkColor* color, float* width) const OVERRIDE;
   virtual void AsValueInto(base::debug::TracedValue* dict) const OVERRIDE;
@@ skipping 33 matching lines @@
   gfx::Rect viewport_rect_for_tile_priority_;
   gfx::Transform screen_space_transform_for_tile_priority_;
 
   friend class PictureLayer;
   DISALLOW_COPY_AND_ASSIGN(PictureLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_PICTURE_LAYER_IMPL_H_