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

Committed: https://code.google.com/p/webrtc/source/detail?r=8257

Committed: https://code.google.com/p/webrtc/source/detail?r=8276

Committed: https://code.google.com/p/webrtc/source/detail?r=8277

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

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#8288}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 6c930c71831b6eda6e85903c505459569a02ad9a

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