Make scroll offset type of float in cc

cc/trees/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_TREES_LAYER_TREE_IMPL_H_
 #define CC_TREES_LAYER_TREE_IMPL_H_
 
 #include <list>
 #include <set>
 #include <string>
@@ skipping 118 matching lines @@
   }
 
   HeadsUpDisplayLayerImpl* hud_layer() { return hud_layer_; }
   void set_hud_layer(HeadsUpDisplayLayerImpl* layer_impl) {
     hud_layer_ = layer_impl;
   }
 
   LayerImpl* InnerViewportScrollLayer() const;
   // This function may return NULL, it is the caller's responsibility to check.
   LayerImpl* OuterViewportScrollLayer() const;
-  gfx::Vector2dF TotalScrollOffset() const;
-  gfx::Vector2dF TotalMaxScrollOffset() const;
+  gfx::ScrollOffset TotalScrollOffset() const;
+  gfx::ScrollOffset TotalMaxScrollOffset() const;
   gfx::Vector2dF TotalScrollDelta() const;
 
   LayerImpl* InnerViewportContainerLayer() const;
   LayerImpl* CurrentlyScrollingLayer() const;
   void SetCurrentlyScrollingLayer(LayerImpl* layer);
   void ClearCurrentlyScrollingLayer();
 
   void SetViewportLayersFromIds(int page_scale_layer_id,
                                 int inner_viewport_scroll_layer_id,
                                 int outer_viewport_scroll_layer_id);
@@ skipping 89 matching lines @@
   bool ViewportSizeInvalid() const;
   void SetViewportSizeInvalid();
   void ResetViewportSizeInvalid();
 
   // Useful for debug assertions, probably shouldn't be used for anything else.
   Proxy* proxy() const;
 
   void SetRootLayerScrollOffsetDelegate(
       LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate);
   void UpdateScrollOffsetDelegate();
-  gfx::Vector2dF GetDelegatedScrollOffset(LayerImpl* layer);
+  gfx::ScrollOffset GetDelegatedScrollOffset(LayerImpl* layer);
 
   // Call this function when you expect there to be a swap buffer.
   // See swap_promise.h for how to use SwapPromise.
   void QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise);
 
   // Take the |new_swap_promise| and append it to |swap_promise_list_|.
   void PassSwapPromises(ScopedPtrVector<SwapPromise>* new_swap_promise);
   void FinishSwapPromises(CompositorFrameMetadata* metadata);
   void BreakSwapPromises(SwapPromise::DidNotSwapReason reason);
 
@@ skipping 131 matching lines @@
   float top_controls_delta_;
   float sent_top_controls_delta_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(LayerTreeImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_IMPL_H_