Animation start scale should be considered for the raster scale

cc/test/animation_test_common.cc

Index: cc/test/animation_test_common.cc
diff --git a/cc/test/animation_test_common.cc b/cc/test/animation_test_common.cc
index d04c5d3bf3343fa0b0c282bd8c90f0219f4330b0..ef852797f23ef9f1c0a544099d855eda50dee964 100644
--- a/cc/test/animation_test_common.cc
+++ b/cc/test/animation_test_common.cc
@@ -174,6 +174,12 @@ bool FakeTransformTransition::PreservesAxisAlignment() const {
   return true;
 }
 
+bool FakeTransformTransition::AnimationStartScale(bool forward_direction,
+                                                  float* start_scale) const {
+  *start_scale = 1.f;
+  return true;
+}
+
 bool FakeTransformTransition::MaximumTargetScale(bool forward_direction,
                                                  float* max_scale) const {
   *max_scale = 1.f;