Delete zoomed_viewport_offset_ and its users.

cc/layer_tree_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_LAYER_TREE_IMPL_H_
 #define CC_LAYER_TREE_IMPL_H_
 
 #include "base/hash_tables.h"
 #include "cc/layer_impl.h"
 
@@ skipping 115 matching lines @@
   bool needs_update_draw_properties() const {
     return needs_update_draw_properties_;
   }
 
   void ClearRenderSurfaces();
 
   bool AreVisibleResourcesReady() const;
 
   const LayerList& RenderSurfaceLayerList() const;
 
+  // These return the size of the root scrollable area and the size of
+  // the user-visible scrolling viewport, in CSS layout coordinates.
   gfx::Size ScrollableSize() const;
+  gfx::SizeF ScrollableViewportSize() const;
 
   LayerImpl* LayerById(int id);
 
   // These should be called by LayerImpl's ctor/dtor.
   void RegisterLayer(LayerImpl* layer);
   void UnregisterLayer(LayerImpl* layer);
 
   AnimationRegistrar* animationRegistrar() const;
 
   void PushPersistedState(LayerTreeImpl* pendingTree);
@@ skipping 31 matching lines @@
 
   bool contents_textures_purged_;
   bool needs_update_draw_properties_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }
 
 #endif  // CC_LAYER_TREE_IMPL_H_