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

cc/test/test_hooks.h

Index: cc/test/test_hooks.h
diff --git a/cc/test/test_hooks.h b/cc/test/test_hooks.h
index 30ebece07227369e63abdf8792e13857c3b6da9f..aec1a00e3d1f6482f706fac5173000f02d1fff3e 100644
--- a/cc/test/test_hooks.h
+++ b/cc/test/test_hooks.h
@@ -129,13 +129,13 @@ class TestHooks : public AnimationDelegate {
 
   // Implementation of AnimationDelegate:
   void NotifyAnimationStarted(base::TimeTicks monotonic_time,
-                              Animation::TargetProperty target_property,
+                              AnimationTargetProperty target_property,
                               int group) override {}
   void NotifyAnimationFinished(base::TimeTicks monotonic_time,
-                               Animation::TargetProperty target_property,
+                               AnimationTargetProperty target_property,
                                int group) override {}
   void NotifyAnimationAborted(base::TimeTicks monotonic_time,
-                              Animation::TargetProperty target_property,
+                              AnimationTargetProperty target_property,
                               int group) override {}
 
   virtual void RequestNewOutputSurface() = 0;