[RootLayerScrolls] Annotate non-fast-scroll regions to correct layer

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 4461452c8d97f31c5d0a97690599655094ba2295..d5405dc977d6bbf3aa9568b0be0ba97b6bf8ac49 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -31,6 +31,7 @@
 #include "core/animation/DocumentAnimations.h"
 #include "core/css/FontFaceSet.h"
 #include "core/dom/AXObjectCache.h"
+#include "core/dom/ClientRectList.h"
 #include "core/dom/DOMNodeIds.h"
 #include "core/dom/ElementVisibilityObserver.h"
 #include "core/dom/Fullscreen.h"
@@ -4380,6 +4381,13 @@ LayoutRect FrameView::scrollIntoView(const LayoutRect& rectInContent,
   return rectInContent;
 }
 
+ClientRectList* FrameView::nonFastScrollableRects() const {
+  if (!layerForScrolling())
+    return ClientRectList::create();
+  return ClientRectList::create(
+      layerForScrolling()->platformLayer()->nonFastScrollableRegion());
+}
+
 IntRect FrameView::scrollCornerRect() const {
   IntRect cornerRect;