Add support for RGB frames in MediaCodecVideoEncoder.

BUG=webrtc:7749

Review-Url: https://codereview.webrtc.org/3002263002
Cr-Original-Commit-Position: refs/heads/master@{#19554}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 160e32c34f629be1fc7e634a085d9dc70a77b908
2 files changed