Add ui::GrabDesktopSnapshot for Windows.

ui/snapshot/snapshot_win.h

Index: ui/snapshot/snapshot_win.h
diff --git a/ui/snapshot/snapshot_win.h b/ui/snapshot/snapshot_win.h
new file mode 100644
index 0000000000000000000000000000000000000000..e521484369cb19af24d9fb2be78643e303c959c8
--- /dev/null
+++ b/ui/snapshot/snapshot_win.h
@@ -0,0 +1,32 @@
+// Copyright 2013 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 UI_SNAPSHOT_SNAPSHOT_WIN_H_
+#define UI_SNAPSHOT_SNAPSHOT_WIN_H_
+
+#include <windows.h>
+
+#include <vector>
+
+#include "ui/snapshot/snapshot_export.h"
+
+namespace gfx {
+class Rect;
+}
+
+namespace ui {
+namespace internal {
+
+// Grabs a snapshot of the desktop. No security checks are done.  This is
+// intended to be used for debugging purposes where no BrowserProcess instance
+// is available (ie. tests). DO NOT use in a result of user action.
+SNAPSHOT_EXPORT bool GrabHwndSnapshot(
+    HWND window_handle,
+    const gfx::Rect& snapshot_bounds,
+    std::vector<unsigned char>* png_representation);
+
+}  // namespace internal
+}  // namespace ui
+
+#endif  // UI_SNAPSHOT_SNAPSHOT_WIN_H_