Fix under-invalidation of frame scrollbar on hover

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

Index: third_party/WebKit/Source/core/frame/FrameView.h
diff --git a/third_party/WebKit/Source/core/frame/FrameView.h b/third_party/WebKit/Source/core/frame/FrameView.h
index e9c1059f1eb30ce1f643cb8f72b2e36ab0e03bce..998e62e1da6690e9ba27ae9424bfffa41b6bed9f 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.h
+++ b/third_party/WebKit/Source/core/frame/FrameView.h
@@ -377,7 +377,6 @@ public:
     IntPoint maximumScrollPosition() const override;
 
     // ScrollableArea interface
-    void scrollControlWasSetNeedsPaintInvalidation() override { }
     void getTickmarks(Vector<IntRect>&) const override;
     IntRect scrollableAreaBoundingBox() const override;
     bool scrollAnimatorEnabled() const override;
@@ -770,7 +769,6 @@ private:
     void updateThrottlingStatus();
 
     // PaintInvalidationCapableScrollableArea
-    LayoutBox& boxForScrollControlPaintInvalidation() const override;
     LayoutScrollbarPart* resizer() const override { return nullptr; }
 
     void checkLayoutInvalidationIsAllowed() const;