OverscrollGlow for mainThread-{BLINK CHANGES}

public/web/WebWidgetClient.h

Index: public/web/WebWidgetClient.h
diff --git a/public/web/WebWidgetClient.h b/public/web/WebWidgetClient.h
index 178c78efa715ec05e28b682b2f31deaa2c1ce711..a8de17bfedc6c60614072375e196b80aa6ceac78 100644
--- a/public/web/WebWidgetClient.h
+++ b/public/web/WebWidgetClient.h
@@ -41,6 +41,8 @@
 
 namespace blink {
 
+struct WebFloatPoint;
+struct WebFloatSize;
 class WebGestureEvent;
 class WebNode;
 class WebString;
@@ -152,6 +154,9 @@ public:
     // Called when a gesture event is handled.
     virtual void didHandleGestureEvent(const WebGestureEvent& event, bool eventCancelled) { }
 
+    // Called when overscrolled on main thread.
+    virtual void didOverscroll(const WebFloatSize& unusedDelta, const WebFloatSize& accumulatedRootOverScroll, const WebFloatPoint& position, const WebFloatSize& velocity) { }
+
     // Called to update if touch events should be sent.
     virtual void hasTouchEventHandlers(bool) { }