cc: Support animating scroll offset

cc/animation/animation.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_ANIMATION_ANIMATION_H_
 #define CC_ANIMATION_ANIMATION_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
@@ skipping 25 matching lines @@
     Aborted,
     // This sentinel must be last.
     RunStateEnumSize
   };
 
   enum TargetProperty {
     Transform = 0,
     Opacity,
     Filter,
     BackgroundColor,
+    ScrollOffset,
     // This sentinel must be last.
     TargetPropertyEnumSize
   };
 
   static scoped_ptr<Animation> Create(scoped_ptr<AnimationCurve> curve,
                                       int animation_id,
                                       int group_id,
                                       TargetProperty target_property);
 
   virtual ~Animation();
@@ skipping 126 matching lines @@
   bool is_controlling_instance_;
 
   bool is_impl_only_;
 
   DISALLOW_COPY_AND_ASSIGN(Animation);
 };
 
 }  // namespace cc
 
 #endif  // CC_ANIMATION_ANIMATION_H_