Adds kind-of-live thumbnail generation for a potential tab switcher.

chrome/browser/renderer_host/backing_store_win.cc

 // 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.
 
 #include "chrome/browser/renderer_host/backing_store.h"
 
 #include "base/gfx/gdi_util.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
 #include "chrome/common/transport_dib.h"
 
 namespace {
 
 // Creates a dib conforming to the height/width/section parameters passed in.
 HANDLE CreateDIB(HDC dc, int width, int height, int color_depth) {
   BITMAPINFOHEADER hdr;
   gfx::CreateBitmapHeaderWithColorDepth(width, height, color_depth, &hdr);
   void* data = NULL;
   HANDLE dib = CreateDIBSection(dc, reinterpret_cast<BITMAPINFO*>(&hdr),
                                 0, &data, NULL, 0);
   DCHECK(data);
   return dib;
 }
 
 }  // namespace
 
 // BackingStore (Windows) ------------------------------------------------------
 
-BackingStore::BackingStore(const gfx::Size& size)
-    : size_(size),
+BackingStore::BackingStore(RenderWidgetHost* widget, const gfx::Size& size)
+    : render_widget_host_(widget),
+      size_(size),
       backing_store_dib_(NULL),
       original_bitmap_(NULL) {
   HDC screen_dc = ::GetDC(NULL);
   color_depth_ = ::GetDeviceCaps(screen_dc, BITSPIXEL);
   // Color depths less than 16 bpp require a palette to be specified. Instead,
   // we specify the desired color depth as 16 which lets the OS to come up
   // with an approximation.
   if (color_depth_ < 16)
     color_depth_ = 16;
   hdc_ = CreateCompatibleDC(screen_dc);
@@ skipping 52 matching lines @@
   ScrollDC(hdc_, dx, dy, NULL, &r, NULL, &damaged_rect);
 
   // TODO(darin): this doesn't work if dx and dy are both non-zero!
   DCHECK(dx == 0 || dy == 0);
 
   // We expect that damaged_rect should equal bitmap_rect.
   DCHECK(gfx::Rect(damaged_rect) == bitmap_rect);
 
   PaintRect(process, bitmap, bitmap_rect);
 }