Differentiate invisible cursor mode and disabled mouse events mode.

content/port/browser/render_widget_host_view_port.h

Index: content/port/browser/render_widget_host_view_port.h
diff --git a/content/port/browser/render_widget_host_view_port.h b/content/port/browser/render_widget_host_view_port.h
index 953296c0b4a9035cc7e89387c5d553d5ea9e087e..d126c3deba7720d931f6feb49f7fd62e48099b56 100644
--- a/content/port/browser/render_widget_host_view_port.h
+++ b/content/port/browser/render_widget_host_view_port.h
@@ -147,6 +147,9 @@ class CONTENT_EXPORT RenderWidgetHostViewPort : public RenderWidgetHostView {
                                       const gfx::Rect& end_rect,
                                       WebKit::WebTextDirection end_direction) {}
 
+  // Notifies the view that the scroll offset has changed.
+  virtual void ScrollOffsetChanged() {}
+
   // Allocate a backing store for this view.
   virtual BackingStore* AllocBackingStore(const gfx::Size& size) = 0;