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

chrome/browser/renderer_host/backing_store_mac.mm

 // Copyright (c) 2006-2008 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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "chrome/browser/renderer_host/backing_store.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
 #include "chrome/browser/renderer_host/render_widget_host_view.h"
 
@@ skipping 81 matching lines @@
     CGContextDrawImage(layer, paint_rect.ToCGRect(), image);
   } else {
     // The layer hasn't been created yet, so draw into the cache bitmap.
     gfx::Rect paint_rect = copy_rect;
     paint_rect.set_y(size_.height() - copy_rect.bottom());
     CGContextDrawImage(cg_bitmap_, paint_rect.ToCGRect(), image);
   }
 }
 
 // Scroll the contents of our CGLayer
-void BackingStore::ScrollRect(base::ProcessHandle process,
-                              TransportDIB* bitmap,
-                              const gfx::Rect& bitmap_rect,
-                              int dx, int dy,
+void BackingStore::ScrollRect(int dx, int dy,
                               const gfx::Rect& clip_rect,
                               const gfx::Size& view_size) {
   DCHECK_NE(static_cast<bool>(cg_layer()), static_cast<bool>(cg_bitmap()));
 
   // "Scroll" the contents of the layer by creating a new CGLayer,
   // copying the contents of the old one into the new one offset by the scroll
   // amount, swapping in the new CGLayer, and then painting in the new data.
   //
   // The Windows code always sets the whole backing store as the source of the
   // scroll. Thus, we only have to worry about pixels which will end up inside
@@ skipping 35 matching lines @@
                                      size_.height() - clip_rect.bottom(),
                                      clip_rect.width(),
                                      clip_rect.height()));
       CGContextDrawImage(new_bitmap,
                          CGRectMake(dx, -dy, size_.width(), size_.height()),
                          bitmap_image);
       CGContextRestoreGState(new_bitmap);
       cg_bitmap_.swap(new_bitmap);
     }
   }
-  // Now paint the new bitmap data
-  PaintRect(process, bitmap, bitmap_rect, bitmap_rect);
-  return;
 }
 
 CGLayerRef BackingStore::CreateCGLayer() {
   // The CGLayer should be optimized for drawing into the containing window,
   // so extract a CGContext corresponding to the window to be passed to
   // CGLayerCreateWithContext.
   NSWindow* window = [render_widget_host()->view()->GetNativeView() window];
   if ([window windowNumber] <= 0) {
     // This catches a nil |window|, as well as windows that exist but that
     // aren't yet connected to WindowServer.
@@ skipping 21 matching lines @@
   CGContextRef context = CGBitmapContextCreate(NULL,
                                                size_.width(), size_.height(),
                                                8, size_.width() * 4,
                                                mac_util::GetSystemColorSpace(),
                                                kCGImageAlphaPremultipliedFirst |
                                                    kCGBitmapByteOrder32Host);
   DCHECK(context);
 
   return context;
 }