Make scroll offset type of float in cc

cc/blink/web_layer_impl.h

 // Copyright 2014 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_BLINK_WEB_LAYER_IMPL_H_
 #define CC_BLINK_WEB_LAYER_IMPL_H_
 
 #include <string>
+#include <utility>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/blink/cc_blink_export.h"
 #include "cc/layers/layer_client.h"
 #include "third_party/WebKit/public/platform/WebCString.h"
 #include "third_party/WebKit/public/platform/WebColor.h"
 #include "third_party/WebKit/public/platform/WebCompositorAnimation.h"
 #include "third_party/WebKit/public/platform/WebFloatPoint.h"
 #include "third_party/WebKit/public/platform/WebLayer.h"
@@ skipping 76 matching lines @@
   virtual void setBackgroundFilters(const blink::WebFilterOperations& filters);
   virtual void setAnimationDelegate(
       blink::WebCompositorAnimationDelegate* delegate);
   virtual bool addAnimation(blink::WebCompositorAnimation* animation);
   virtual void removeAnimation(int animation_id);
   virtual void removeAnimation(int animation_id,
                                blink::WebCompositorAnimation::TargetProperty);
   virtual void pauseAnimation(int animation_id, double time_offset);
   virtual bool hasActiveAnimation();
   virtual void setForceRenderSurface(bool force);
+  // TODO(miletus): Remove the WebPoint version once blink side starts to
+  // use the std:pair<double, double> version.
+  virtual void setScrollPositionFloat(const std::pair<double, double>&);
+  virtual std::pair<double, double> scrollPositionFloat() const;
   virtual void setScrollPosition(blink::WebPoint position);
   virtual blink::WebPoint scrollPosition() const;
   virtual void setScrollClipLayer(blink::WebLayer* clip_layer);
   virtual bool scrollable() const;
   virtual void setUserScrollable(bool horizontal, bool vertical);
   virtual bool userScrollableHorizontal() const;
   virtual bool userScrollableVertical() const;
   virtual void setHaveWheelEventHandlers(bool have_wheel_event_handlers);
   virtual bool haveWheelEventHandlers() const;
   virtual void setHaveScrollEventHandlers(bool have_scroll_event_handlers);
@@ skipping 28 matching lines @@
 
  private:
   scoped_ptr<WebToCCAnimationDelegateAdapter> animation_delegate_adapter_;
 
   DISALLOW_COPY_AND_ASSIGN(WebLayerImpl);
 };
 
 }  // namespace cc_blink
 
 #endif  // CC_BLINK_WEB_LAYER_IMPL_H_