Reland r107720 - Enable the new layer animation framework.

ui/gfx/compositor/layer_animation_element.h

 // Copyright (c) 2011 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 UI_GFX_COMPOSITOR_LAYER_ANIMATION_ELEMENT_H_
 #define UI_GFX_COMPOSITOR_LAYER_ANIMATION_ELEMENT_H_
 #pragma once
 
 #include <set>
 
@@ skipping 53 matching lines @@
   // Updates the delegate to the appropriate value for |t|, which is in the
   // range [0, 1] (0 for initial, and 1 for final). If the animation is not
   // aborted, it is guaranteed that Progress will eventually be called with
   // t = 1.0.
   void Progress(double t, LayerAnimationDelegate* delegate);
 
   // Called if the animation is not allowed to complete. This may be called
   // before OnStarted or Progress.
   void Abort();
 
+  // Sets the delegate to the target value.
+  void SetTarget(LayerAnimationDelegate* delegate) const;

[sky, 2011/10/20 20:30:30]

This is an odd way to extract the target value. How about:

 struct TargetValue {
    transform, opacity ...
  };

 GetTargetValue(TargetValue* target_value);

+
   // The properties that the element modifies.
   const AnimatableProperties& properties() const { return properties_; }
 
   // The duration of the animation
   base::TimeDelta duration() const { return duration_; }
 
  protected:
   // Called once each time the animation element is run before any call to
   // OnProgress.
   virtual void OnStart(LayerAnimationDelegate* delegate) = 0;
   virtual void OnProgress(double t, LayerAnimationDelegate* delegate) = 0;
+  virtual void OnSetTarget(LayerAnimationDelegate* delegate) const = 0;
   virtual void OnAbort() = 0;
 
  private:
   bool first_frame_;
   const AnimatableProperties properties_;
   const base::TimeDelta duration_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimationElement);
 };
 
 }  // namespace ui
 
 #endif  // UI_GFX_COMPOSITOR_LAYER_ANIMATION_ELEMENT_H_