Animations: Introduce compositor AnimationPlayer and AnimationTimeline.

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 6863b785e5b71a64838b9d1abbe79b3e3d0f2081..5c2f1edddcd40f084dfec8d84ed97d8a132ba447 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -4381,6 +4381,12 @@ void WebViewImpl::scheduleAnimation()
         m_client->scheduleAnimation();
 }
 
+void WebViewImpl::setCompositorAnimationTimeline(WebCompositorAnimationTimeline* timeline)
+{
+    if (m_layerTreeView)
+        m_layerTreeView->setCompositorAnimationTimeline(timeline);
+}
+
 void WebViewImpl::initializeLayerTreeView()
 {
     if (m_client) {