Blink Compositor Animation: Introduce CompositorAnimationHost correctly.

third_party/WebKit/Source/platform/testing/WebLayerTreeViewImplForTesting.cpp

Index: third_party/WebKit/Source/platform/testing/WebLayerTreeViewImplForTesting.cpp
diff --git a/third_party/WebKit/Source/platform/testing/WebLayerTreeViewImplForTesting.cpp b/third_party/WebKit/Source/platform/testing/WebLayerTreeViewImplForTesting.cpp
index 9bcb43fdd6903cd4ba709123d5faf441914da313..fb749cad5d8523273d33b9bd322ec34d00cec622 100644
--- a/third_party/WebKit/Source/platform/testing/WebLayerTreeViewImplForTesting.cpp
+++ b/third_party/WebKit/Source/platform/testing/WebLayerTreeViewImplForTesting.cpp
@@ -62,16 +62,8 @@ void WebLayerTreeViewImplForTesting::clearRootLayer() {
   m_layerTreeHost->GetLayerTree()->SetRootLayer(scoped_refptr<cc::Layer>());
 }
 
-void WebLayerTreeViewImplForTesting::attachCompositorAnimationTimeline(
-    cc::AnimationTimeline* compositorTimeline) {
-  DCHECK(m_animationHost);
-  m_animationHost->AddAnimationTimeline(compositorTimeline);
-}
-
-void WebLayerTreeViewImplForTesting::detachCompositorAnimationTimeline(
-    cc::AnimationTimeline* compositorTimeline) {
-  DCHECK(m_animationHost);
-  m_animationHost->RemoveAnimationTimeline(compositorTimeline);
+cc::AnimationHost* WebLayerTreeViewImplForTesting::compositorAnimationHost() {
+  return m_animationHost.get();
 }
 
 void WebLayerTreeViewImplForTesting::setViewportSize(