Give OOPIF FrameViews their own scroll animation timelines and hosts

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

Index: third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
diff --git a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
index d56224c2612f383813407fadac64037f003bbac2..1cdb25ed3a287efb4d2e0969c3fb36b72f033199 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -1882,18 +1882,12 @@ void PaintLayerScrollableArea::resetRebuildScrollbarLayerFlags() {
 
 CompositorAnimationHost* PaintLayerScrollableArea::compositorAnimationHost()
     const {
-  if (ScrollingCoordinator* coordinator = getScrollingCoordinator())
-    return coordinator->compositorAnimationHost();
-
-  return nullptr;
+  return m_layer.layoutObject()->frameView()->compositorAnimationHost();

[bokan, 2017/01/17 20:40:16]

VisualViewport also calls this via ScrollingCoordinator but I forget how
VisualViewport works with OOPIF, does just the top level renderer have one? Or
do we just rely on OOP renderers never calling into their own instances of it?

[kenrb, 2017/01/19 19:07:40]

There are VisualViewports in OOPIF processes, but they mostly do nothing. I
think we store the root viewport size in it because of cases where a remote main
frame gets swapped to a local main frame, but that's it.

[bokan, 2017/01/19 20:05:39]

Ok, in that case, if it works please add DCHECKs inside
VisualViewport::compositorAnimationHost and compositorAnimationTimeline that
ensure we never call those from an OOPIF

[kenrb, 2017/01/19 21:36:19]

I will do this in a follow up CL.

 }
 
 CompositorAnimationTimeline*
 PaintLayerScrollableArea::compositorAnimationTimeline() const {
-  if (ScrollingCoordinator* coordinator = getScrollingCoordinator())
-    return coordinator->compositorAnimationTimeline();
-
-  return nullptr;
+  return m_layer.layoutObject()->frameView()->compositorAnimationTimeline();
 }
 
 PaintLayerScrollableArea*