Allow painting multiple paint rects....

chrome/renderer/paint_aggregator.h

 // Copyright (c) 2009 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 CHROME_RENDERER_PAINT_AGGREGATOR_H_
 #define CHROME_RENDERER_PAINT_AGGREGATOR_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 25 matching lines @@
     gfx::Point scroll_delta;
     gfx::Rect scroll_rect;
     std::vector<gfx::Rect> paint_rects;
   };
 
   // There is a PendingUpdate if InvalidateRect or ScrollRect were called and
   // ClearPendingUpdate was not called.
   bool HasPendingUpdate() const;
   void ClearPendingUpdate();
 
-  const PendingUpdate& GetPendingUpdate() const { return update_; }
+  const PendingUpdate& GetPendingUpdate();

[brettw, 2010/12/06 19:09:29]

It kind of sucks that this function modifies the update inside the paint
aggregator out from under you. Normally I wouldn't expect this to happen for a
functionc alled GetFoo().

Maybe we can rename the function, like CoalesceAndGetPendingUpdate()?

 
   // The given rect should be repainted.
   void InvalidateRect(const gfx::Rect& rect);
 
   // The given rect should be scrolled by the given amounts.
   void ScrollRect(int dx, int dy, const gfx::Rect& clip_rect);
 
  private:
   gfx::Rect ScrollPaintRect(const gfx::Rect& paint_rect, int dx, int dy) const;
   bool ShouldInvalidateScrollRect(const gfx::Rect& rect) const;
   void InvalidateScrollRect();
   void CombinePaintRects();
 
   PendingUpdate update_;
 };
 
 #endif  // CHROME_RENDERER_PAINT_AGGREGATOR_H_