Add GrabWindowSnapshotAsync tests

ui/snapshot/snapshot_win.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 "ui/snapshot/snapshot_win.h"
 
 #include "base/callback.h"
 #include "base/win/scoped_gdi_object.h"
 #include "base/win/scoped_hdc.h"
 #include "base/win/scoped_select_object.h"
@@ skipping 101 matching lines @@
 }
 
 bool GrabWindowSnapshot(gfx::NativeWindow window_handle,
                         std::vector<unsigned char>* png_representation,
                         const gfx::Rect& snapshot_bounds) {
   DCHECK(window_handle);
   return internal::GrabHwndSnapshot(window_handle, snapshot_bounds,
                                     png_representation);
 }
 
-SNAPSHOT_EXPORT void GrapWindowSnapshotAsync(
+void GrapWindowSnapshotAsync(
     gfx::NativeWindow window,
     const gfx::Rect& snapshot_bounds,
     const gfx::Size& target_size,
     scoped_refptr<base::TaskRunner> background_task_runner,
     GrapWindowSnapshotAsyncCallback callback) {
   NOTIMPLEMENTED();
 }
 
+void GrabWindowSnapshotAsync(
+    gfx::NativeWindow window,
+    const gfx::Rect& source_rect,
+    scoped_refptr<base::TaskRunner> background_task_runner,
+    const GrabWindowSnapshotAsyncCallback& callback) {
+  NOTIMPLEMENTED();
+}
+
 #endif  // !defined(USE_AURA)
 
 }  // namespace ui