Cleanup: unify rotation to be enum based instead of int for degree.

Split from https://webrtc-codereview.appspot.com/37029004/

BUG=4145
R=pthatcher@webrtc.org, stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/37129004

Cr-Commit-Position: refs/heads/master@{#8257}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8257 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/common_video/rotation.h

@@ -0,0 +1,33 @@
+/*
+ *  Copyright (c) 2015 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_COMMON_VIDEO_ROTATION_H_
+#define WEBRTC_COMMON_VIDEO_ROTATION_H_
+
+#include "webrtc/base/common.h"
+
+namespace webrtc {
+
+// enum for clockwise rotation.
+enum VideoFrameRotation {
+  VideoFrameRotation_0 = 0,
+  VideoFrameRotation_90 = 90,
+  VideoFrameRotation_180 = 180,
+  VideoFrameRotation_270 = 270
+};
+
+inline VideoFrameRotation ClockwiseRotationFromDegree(int rotation) {
+  ASSERT(rotation == 0 || rotation == 90 || rotation == 180 || rotation == 270);
+  return static_cast<webrtc::VideoFrameRotation>(rotation);
+}
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_COMMON_VIDEO_ROTATION_H_