Add Linux support for getting the thumbnail and wire into the switcher.

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 39 matching lines @@
   const gfx::Size& size() { return size_; }
 
 #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_; };
+
   // Copy from the server-side backing store to the target window
   //   display: the display of the backing store and target window
   //   damage: the area to copy
   //   target: the X id of the target window
   void ShowRect(const gfx::Rect& damage, XID target);
 
-  // Paints the server-side backing store data to a SkBitmap.
-  SkBitmap* PaintRectToBitmap(const gfx::Rect& rect);
+  // Paints the server-side backing store data to a SkBitmap. On failure, the
+  // return bitmap will be isNull().
+  SkBitmap PaintRectToBitmap(const gfx::Rect& rect);
 #endif
 
   // Paints the bitmap from the renderer onto the backing store.
   void PaintRect(base::ProcessHandle process,
                  TransportDIB* bitmap,
                  const gfx::Rect& bitmap_rect);
 
   // Scrolls the given rect in the backing store, replacing the given region
   // identified by |bitmap_rect| by the bitmap in the file identified by the
   // given file handle.
@@ skipping 47 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_