Add DesktopFrame rotation functions

webrtc/modules/desktop_capture/test_utils.h

+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_DESKTOP_CAPTURE_TEST_UTILS_H_
+#define WEBRTC_MODULES_DESKTOP_CAPTURE_TEST_UTILS_H_
+
+#include "webrtc/modules/desktop_capture/desktop_frame.h"
+
+namespace webrtc {
+
+// Clears a DesktopFrame |frame| by setting its data() into 0.
+void ClearDesktopFrame(DesktopFrame* frame);
+
+// Compares size() and data() of two DesktopFrames |left| and |right|.
+bool DesktopFrameDataEquals(const DesktopFrame& left,
+                            const DesktopFrame& right);
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_DESKTOP_CAPTURE_TEST_UTILS_H_