Combine ViewHostMsg_{Paint,Scroll}Rect into one IPC....

chrome/browser/renderer_host/render_widget_host.h

Index: chrome/browser/renderer_host/render_widget_host.h
===================================================================
--- chrome/browser/renderer_host/render_widget_host.h	(revision 34937)
+++ chrome/browser/renderer_host/render_widget_host.h	(working copy)
@@ -38,9 +38,8 @@
 class RenderWidgetHostPaintingObserver;
 class TransportDIB;
 class WebCursor;
-struct ViewHostMsg_PaintRect_Params;
-struct ViewHostMsg_ScrollRect_Params;
 struct ViewHostMsg_ShowPopup_Params;
+struct ViewHostMsg_UpdateRect_Params;
 
 // This class manages the browser side of a browser<->renderer HWND connection.
 // The HWND lives in the browser process, and windows events are sent over
@@ -413,8 +412,7 @@
   void OnMsgRenderViewGone();
   void OnMsgClose();
   void OnMsgRequestMove(const gfx::Rect& pos);
-  void OnMsgPaintRect(const ViewHostMsg_PaintRect_Params& params);
-  void OnMsgScrollRect(const ViewHostMsg_ScrollRect_Params& params);
+  void OnMsgUpdateRect(const ViewHostMsg_UpdateRect_Params& params);
   void OnMsgInputEventAck(const IPC::Message& message);
   void OnMsgFocus();
   void OnMsgBlur();
@@ -444,10 +442,7 @@
   // Scrolls the given |clip_rect| in the backing by the given dx/dy amount. The
   // |dib| and its corresponding location |bitmap_rect| in the backing store
   // is the newly painted pixels by the renderer.
-  void ScrollBackingStoreRect(TransportDIB* dib,
-                              const gfx::Rect& bitmap_rect,
-                              int dx, int dy,
-                              const gfx::Rect& clip_rect,
+  void ScrollBackingStoreRect(int dx, int dy, const gfx::Rect& clip_rect,
                               const gfx::Size& view_size);
 
   // Called by OnMsgInputEventAck() to process a keyboard event ack message.