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

chrome/renderer/render_widget.h

Index: chrome/renderer/render_widget.h
===================================================================
--- chrome/renderer/render_widget.h	(revision 34937)
+++ chrome/renderer/render_widget.h	(working copy)
@@ -142,8 +142,7 @@
                         const gfx::Rect& resizer_rect);
   void OnWasHidden();
   void OnWasRestored(bool needs_repainting);
-  void OnPaintRectAck();
-  void OnScrollRectAck();
+  void OnUpdateRectAck();
   void OnRequestMoveAck();
   void OnHandleInputEvent(const IPC::Message& message);
   void OnMouseCaptureLost();
@@ -167,16 +166,11 @@
 
   bool is_hidden() const { return is_hidden_; }
 
-  // True if a PaintRect_ACK message is pending.
-  bool paint_reply_pending() const {
-    return paint_reply_pending_;
+  // True if an UpdateRect_ACK message is pending.
+  bool update_reply_pending() const {
+    return update_reply_pending_;
   }
 
-  // True if a ScrollRect_ACK message is pending.
-  bool scroll_reply_pending() const {
-    return current_scroll_buf_ != NULL;
-  }
-
   bool next_paint_is_resize_ack() const;
   bool next_paint_is_restore_ack() const;
   void set_next_paint_is_resize_ack();
@@ -238,22 +232,20 @@
   // The size of the RenderWidget.
   gfx::Size size_;
 
-  // Transport DIBs that are currently in use to transfer an image to the
-  // browser.
+  // The TransportDIB that is being used to transfer an image to the browser.
   TransportDIB* current_paint_buf_;
-  TransportDIB* current_scroll_buf_;
 
   PaintAggregator paint_aggregator_;
 
   // The area that must be reserved for drawing the resize corner.
   gfx::Rect resizer_rect_;
 
-  // Flags for the next ViewHostMsg_PaintRect message.
+  // Flags for the next ViewHostMsg_UpdateRect message.
   int next_paint_flags_;
 
-  // True if we are expecting a PaintRect_ACK message (i.e., that a PaintRect
-  // message has been sent).
-  bool paint_reply_pending_;
+  // True if we are expecting an UpdateRect_ACK message (i.e., that a
+  // UpdateRect message has been sent).
+  bool update_reply_pending_;
 
   // Set to true if we should ignore RenderWidget::Show calls.
   bool did_show_;