CC Animation: Move ElementId from animation to trees.

cc/test/animation_test_common.h

Index: cc/test/animation_test_common.h
diff --git a/cc/test/animation_test_common.h b/cc/test/animation_test_common.h
index 588448fb73bb6e075e826c4ad751bd8f3acb5868..eace8da6661d7745e61ec829ddd6855260a416c9 100644
--- a/cc/test/animation_test_common.h
+++ b/cc/test/animation_test_common.h
@@ -8,10 +8,10 @@
 #include "cc/animation/animation.h"
 #include "cc/animation/animation_curve.h"
 #include "cc/animation/animation_timeline.h"
-#include "cc/animation/element_id.h"
 #include "cc/animation/transform_operations.h"
 #include "cc/output/filter_operations.h"
 #include "cc/test/geometry_test_utils.h"
+#include "cc/trees/element_id.h"
 
 namespace cc {
 class AnimationPlayer;