Make RootScroller set the outer viewport scroll layer in the compositor

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

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 2d84b43ae9109b0c87637d76bc20790eb18184be..1ac8620bf2eb27e8fbafb478b402bdd5d5d7ceff 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -79,6 +79,7 @@
 #include "core/page/FrameTree.h"
 #include "core/page/Page.h"
 #include "core/page/scrolling/ChildViewportScrollCallback.h"
+#include "core/page/scrolling/RootScrollerController.h"
 #include "core/page/scrolling/RootViewportScrollCallback.h"
 #include "core/page/scrolling/ScrollingCoordinator.h"
 #include "core/paint/FramePainter.h"
@@ -2547,6 +2548,7 @@ void FrameView::updateLifecyclePhasesInternal(DocumentLifecycle::LifecycleState
                 if (view.compositor()->inCompositingMode())
                     scrollingCoordinator()->updateAfterCompositingChangeIfNeeded();
 
+                m_frame->document()->rootScrollerController()->didUpdateCompositing();
                 updateCompositedSelectionIfNeeded();
             }
         }