change backing store cache to be memory-based rather than count

chrome/browser/renderer_host/backing_store.h

 // 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.
 
 #ifndef CHROME_BROWSER_RENDERER_HOST_BACKING_STORE_H_
 #define CHROME_BROWSER_RENDERER_HOST_BACKING_STORE_H_
 
 #include "base/basictypes.h"
 #include "base/gfx/rect.h"
 #include "base/gfx/size.h"
@@ skipping 31 matching lines @@
 
   // This is for unittesting only. An object constructed using this constructor
   // will silently ignore all paints
   BackingStore(RenderWidgetHost* widget, const gfx::Size& size);
 #endif
   ~BackingStore();
 
   RenderWidgetHost* render_widget_host() const { return render_widget_host_; }
   const gfx::Size& size() { return size_; }
 
+  // The number of bytes that this backing store consumes.  This should rougly

[darin (slow to review), 2009/06/24 22:21:24]

nit: roughly

+  // be size_.GetArea() * bytes per pixel.
+  size_t MemorySize();
+
 #if defined(OS_WIN)
   HDC hdc() { return hdc_; }
 
   // Returns true if we should convert to the monitor profile when painting.
   static bool ColorManagementEnabled();
 #elif defined(OS_MACOSX)
   skia::PlatformCanvas* canvas() { return &canvas_; }
 #elif defined(OS_LINUX)
   Display* display() const { return display_; }
   XID root_window() const { return root_window_; };
@@ skipping 67 matching lines @@
   // This is the RENDER picture pointing at |pixmap_|.
   XID picture_;
   // This is a default graphic context, used in XCopyArea
   void* pixmap_gc_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(BackingStore);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_BACKING_STORE_H_