Give OOPIF FrameViews their own scroll animation timelines and hosts

third_party/WebKit/Source/core/frame/VisualViewport.cpp

Index: third_party/WebKit/Source/core/frame/VisualViewport.cpp
diff --git a/third_party/WebKit/Source/core/frame/VisualViewport.cpp b/third_party/WebKit/Source/core/frame/VisualViewport.cpp
index 7899bfb739fa6ae38580bd46562acd8c67d122a4..38b97c84f41a28cb13eedfd8e750a48d5448664e 100644
--- a/third_party/WebKit/Source/core/frame/VisualViewport.cpp
+++ b/third_party/WebKit/Source/core/frame/VisualViewport.cpp
@@ -801,12 +801,14 @@ bool VisualViewport::shouldDisableDesktopWorkarounds() const {
 }
 
 CompositorAnimationHost* VisualViewport::compositorAnimationHost() const {
+  DCHECK(frameHost().page().mainFrame()->isLocalFrame());
   ScrollingCoordinator* c = frameHost().page().scrollingCoordinator();
   return c ? c->compositorAnimationHost() : nullptr;
 }
 
 CompositorAnimationTimeline* VisualViewport::compositorAnimationTimeline()
     const {
+  DCHECK(frameHost().page().mainFrame()->isLocalFrame());
   ScrollingCoordinator* c = frameHost().page().scrollingCoordinator();
   return c ? c->compositorAnimationTimeline() : nullptr;
 }