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

ui/compositor/test/layer_animator_test_controller.cc

 // Copyright (c) 2013 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.
 
 #include "cc/animation/animation.h"
 #include "ui/compositor/layer_animation_sequence.h"
 #include "ui/compositor/test/layer_animator_test_controller.h"
 #include "ui/gfx/frame_time.h"
 #include "ui/gfx/rect.h"
 
@@ skipping 30 matching lines @@
       continue;
 
     LayerAnimationElement* element = sequence->CurrentElement();
     if (!(element->properties() & animatable_property))
       continue;
 
     if (!element->Started() ||
         element->effective_start_time() != base::TimeTicks())
       continue;
 
-    animator_->OnThreadedAnimationStarted(cc::AnimationEvent(
-        cc::AnimationEvent::Started,
-        0,
-        element->animation_group_id(),
-        threaded_properties[i],
-        (gfx::FrameTime::Now() - base::TimeTicks()).InSecondsF()));
+    animator_->OnThreadedAnimationStarted(
+        cc::AnimationEvent(cc::AnimationEvent::Started,
+                           0,
+                           element->animation_group_id(),
+                           threaded_properties[i],
+                           gfx::FrameTime::Now()));
   }
 }
 
 }  // namespace ui