content: Remove unused RenderViewObserver::DidHandleTouchEvent.

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index ecd41bbede2e548563f17326dff638dfe93a4f13..b708ea1f9cdd577a76ecc94d18a903e9e33979e3 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -561,10 +561,6 @@ class CONTENT_EXPORT RenderWidget
   // just handled.
   virtual void DidHandleMouseEvent(const blink::WebMouseEvent& event) {}
 
-  // Called by OnHandleInputEvent() to notify subclasses that a touch event was
-  // just handled.
-  virtual void DidHandleTouchEvent(const blink::WebTouchEvent& event) {}
-
   // Called by OnHandleInputEvent() to forward a mouse wheel event to the
   // compositor thread, to effect the elastic overscroll effect.
   void ObserveWheelEventAndResult(const blink::WebMouseWheelEvent& wheel_event,