Introduce XGetImage() for GrabWindowSnapshot() in ChromeOS.

chrome/browser/ui/window_snapshot/window_snapshot_aura.cc

 // Copyright (c) 2012 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/ui/window_snapshot/window_snapshot.h"
 
 #include "base/logging.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/aura/window.h"
+#include "ui/aura/root_window.h"
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/rect.h"
 
 namespace browser {
 
 bool GrabWindowSnapshot(gfx::NativeWindow window,
                         std::vector<unsigned char>* png_representation,
                         const gfx::Rect& snapshot_bounds) {
+#if defined(OS_CHROMEOS)

[Daniel Erat, 2012/05/14 23:17:40]

Should this be OS_LINUX?  I don't see anything Chrome OS-specific here.

[Jun Mukai, 2012/05/15 22:39:24]

Done.

+  // We use XGetImage() for ChromeOS for the performance reason.

[Daniel Erat, 2012/05/14 23:17:40]

nit: s/the performance reason/performance reasons/

Does Windows not have the same performance problems?

[Jun Mukai, 2012/05/15 22:39:24]

Done.

+  // See crbug.com/122720
+  return window->GetRootWindow()->GrabWindowSnapshot(
+      png_representation, snapshot_bounds);
+#else
   ui::Compositor* compositor = window->layer()->GetCompositor();
 
   gfx::Rect read_pixels_bounds = snapshot_bounds;
 
   // When not in compact mode we must take into account the window's position on
   // the desktop.
   read_pixels_bounds.set_origin(
       snapshot_bounds.origin().Add(window->bounds().origin()));
   gfx::Rect read_pixels_bounds_in_pixel =
       ui::ConvertRectToPixel(window->layer(), read_pixels_bounds);
 
   DCHECK_GE(compositor->size().width(), read_pixels_bounds_in_pixel.right());
   DCHECK_GE(compositor->size().height(), read_pixels_bounds_in_pixel.bottom());
   DCHECK_LE(0, read_pixels_bounds.x());
   DCHECK_LE(0, read_pixels_bounds.y());
 
   SkBitmap bitmap;
   if (!compositor->ReadPixels(&bitmap, read_pixels_bounds_in_pixel))
     return false;
 
   unsigned char* pixels = reinterpret_cast<unsigned char*>(bitmap.getPixels());
 
   gfx::PNGCodec::Encode(pixels, gfx::PNGCodec::FORMAT_BGRA,
                         read_pixels_bounds_in_pixel.size(),
                         bitmap.rowBytes(), true,
                         std::vector<gfx::PNGCodec::Comment>(),
                         png_representation);
   return true;
+#endif
 }
 
 }  // namespace browser