Android: Improve handling of RGB texture frames

In the transition period when we have both VideoRenderer.Callbacks and
VideoSinks, and VideoRenderer.I420Frames and VideoFrames, the adapters
between them does not handle RGB frames correctly. This CL improves the
situation somewhat, and at least gives clearer error messages.

BUG=webrtc:7749

Review-Url: https://codereview.webrtc.org/3017433002
Cr-Original-Commit-Position: refs/heads/master@{#19817}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 2ab9879af0ef661b9afde3f1a56ef7073c4006cf
2 files changed