[RootLayerScrolls] Fix frame scrolling layer in ScrollingCoordinator

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 566d72f847410969a7f382933f7661954dd61a78..b919dcb7664c0aeba42a43e1d823990c77c3992c 100644
--- a/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
+++ b/third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp
@@ -566,6 +566,10 @@ IntSize PaintLayerScrollableArea::contentsSize() const {
   return IntSize(pixelSnappedScrollWidth(), pixelSnappedScrollHeight());
 }
 
+bool PaintLayerScrollableArea::isScrollable() const {
+  return scrollsOverflow();
+}
+
 IntPoint PaintLayerScrollableArea::lastKnownMousePosition() const {
   return box().frame() ? box().frame()->eventHandler().lastKnownMousePosition()
                        : IntPoint();