Introduce XGetImage() for GrabWindowSnapshot() in ChromeOS.

BUG=119492
TEST=manually done

Review URL: https://chromiumcodereview.appspot.com/10386124

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137556 0039d316-1c4b-4281-b951-d872f2087c98
void RootWindowHostWin::SetCursor(gfx::NativeCursor native_cursor) {
  if (native_cursor == ui::kCursorCustom)
    return;
  const wchar_t* cursor_id = GetCursorId(native_cursor);
  ::SetCursor(LoadCursor(NULL, cursor_id));
}

void RootWindowHostWin::SetCursor(gfx::NativeCursor native_cursor) {
  if (native_cursor == ui::kCursorCustom)
    return;
  const wchar_t* cursor_id = GetCursorId(native_cursor);
  ::SetCursor(LoadCursor(NULL, cursor_id));
}
