PSA: Android SurfaceTextureHelper will start outputting VideoFrames

[mag...@webrtc.org]

SurfaceTextureHelper currently calls its listener with a texture id, a transform matrix, and a timestamp. This is close to being a complete frame, but not quite. The listener has to call back into SurfaceTextureHelper, passing the texture resolution, in order to create a frame.

SurfaceTextureHelper has now been updated to output org.webrtc.VideoFrames directly, and the old methods have been deprecated. These methods will be removed in two weeks.

See https://bugs.chromium.org/p/webrtc/issues/detail?id=9412 for more information.