CC Animation: Expose TargetProperty enum to be aliased in Blink Platform.

cc/animation/animation_unittest.cc

Index: cc/animation/animation_unittest.cc
diff --git a/cc/animation/animation_unittest.cc b/cc/animation/animation_unittest.cc
index 5a089120b4aa6bba70179d8302f999963283d746..76a49099b4aead5e533f1b00c8b3a33d0ec227d5 100644
--- a/cc/animation/animation_unittest.cc
+++ b/cc/animation/animation_unittest.cc
@@ -23,7 +23,7 @@ scoped_ptr<Animation> CreateAnimation(double iterations,
                                       double playback_rate) {
   scoped_ptr<Animation> to_return(
       Animation::Create(make_scoped_ptr(new FakeFloatAnimationCurve(duration)),
-                        0, 1, Animation::OPACITY));
+                        0, 1, AnimationTargetProperty::OPACITY));
   to_return->set_iterations(iterations);
   to_return->set_playback_rate(playback_rate);
   return to_return;