Bundle main thread overscroll data with event ack messages

content/renderer/render_widget.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_RENDER_WIDGET_H_
 #define CONTENT_RENDERER_RENDER_WIDGET_H_
 
 #include <deque>
 #include <map>
 
@@ skipping 69 matching lines @@
 class CompositorDependencies;
 class ExternalPopupMenu;
 class FrameSwapMessageQueue;
 class PepperPluginInstanceImpl;
 class RenderFrameImpl;
 class RenderFrameProxy;
 class RenderWidgetCompositor;
 class RenderWidgetTest;
 class ResizingModeSelector;
 struct ContextMenuParams;
+struct DidOverscrollParams;
 struct WebPluginGeometry;
 
 // RenderWidget provides a communication bridge between a WebWidget and
 // a RenderWidgetHost, the latter of which lives in a different process.
 class CONTENT_EXPORT RenderWidget
     : public IPC::Listener,
       public IPC::Sender,
       NON_EXPORTED_BASE(virtual public blink::WebWidgetClient),
       public base::RefCounted<RenderWidget> {
  public:
@@ skipping 571 matching lines @@
 
   // Indicates the display mode.
   blink::WebDisplayMode display_mode_;
 
   // Indicates whether we have been focused/unfocused by the browser.
   bool has_focus_;
 
   // Are we currently handling an input event?
   bool handling_input_event_;
 
+  // Used to intercept overscroll notifications while an event is being
+  // handled. If the event causes overscroll, the overscroll metadata can be
+  // bundled in the event ack, saving an IPC.  Note that we must continue
+  // supporting overscroll IPC notifications due to fling animation updates.
+  scoped_ptr<DidOverscrollParams>* handling_event_overscroll_;
+
   // Are we currently handling an ime event?
   bool handling_ime_event_;
 
   // Type of the input event we are currently handling.
   blink::WebInputEvent::Type handling_event_type_;
 
   // Whether we should not send ack for the current mouse move.
   bool ignore_ack_for_mouse_move_from_debugger_;
 
   // True if we have requested this widget be closed.  No more messages will
@@ skipping 127 matching lines @@
   ui::MenuSourceType context_menu_source_type_;
   bool has_host_context_menu_location_;
   gfx::Point host_context_menu_location_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_WIDGET_H_