CC::Animations should use TimeTicks & TimeDelta to represent time

cc/input/page_scale_animation.h

Index: cc/input/page_scale_animation.h
diff --git a/cc/input/page_scale_animation.h b/cc/input/page_scale_animation.h
index c7856e1d0b256abeafa188811e5451dbf4a2eda8..825a0d09c2dcbe524f46532d008f9730c5fddba8 100644
--- a/cc/input/page_scale_animation.h
+++ b/cc/input/page_scale_animation.h
@@ -7,10 +7,15 @@
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
 #include "ui/gfx/size.h"
 #include "ui/gfx/vector2d_f.h"
 
 namespace cc {
+
+using base::TimeTicks;
+using base::TimeDelta;
+
 class TimingFunction;
 
 // A small helper class that does the math for zoom animations, primarily for
@@ -52,19 +57,19 @@ class PageScaleAnimation {
   // These should be called before the first frame of animation to initialize
   // the start time. StartAnimation should only be called once after creation.
   bool IsAnimationStarted() const;
-  void StartAnimation(double time);
+  void StartAnimation(base::TimeTicks time);
 
   // Call these functions while the animation is in progress to output the
   // current state.
-  gfx::Vector2dF ScrollOffsetAtTime(double time) const;
-  float PageScaleFactorAtTime(double time) const;
-  bool IsAnimationCompleteAtTime(double time) const;
+  gfx::Vector2dF ScrollOffsetAtTime(base::TimeTicks time) const;
+  float PageScaleFactorAtTime(base::TimeTicks time) const;
+  bool IsAnimationCompleteAtTime(base::TimeTicks time) const;
 
   // The following methods return state which is invariant throughout the
   // course of the animation.
-  double start_time() const { return start_time_; }
-  double duration() const { return duration_; }
-  double end_time() const { return start_time_ + duration_; }
+  TimeTicks start_time() const { return start_time_; }
+  TimeDelta duration() const { return duration_; }
+  TimeTicks end_time() const { return start_time_ + duration_; }
   gfx::Vector2dF target_scroll_offset() const { return target_scroll_offset_; }
   float target_page_scale_factor() const { return target_page_scale_factor_; }
 
@@ -82,7 +87,7 @@ class PageScaleAnimation {
 
   gfx::SizeF StartViewportSize() const;
   gfx::SizeF TargetViewportSize() const;
-  float InterpAtTime(double time) const;
+  float InterpAtTime(base::TimeTicks time) const;
   gfx::SizeF ViewportSizeAt(float interp) const;
   gfx::Vector2dF ScrollOffsetAt(float interp) const;
   gfx::Vector2dF AnchorAt(float interp) const;
@@ -100,8 +105,8 @@ class PageScaleAnimation {
   gfx::SizeF viewport_size_;
   gfx::SizeF root_layer_size_;
 
-  double start_time_;
-  double duration_;
+  TimeTicks start_time_;
+  TimeDelta duration_;
 
   scoped_ptr<TimingFunction> timing_function_;