Adds the VideoEncoderFactory interface and implements it for use with HardwareVideoEncoder. This uses MediaCodecVideoEncoder's initialization code as an example.
BUG=webrtc:7760
Change-Id: I9fbc93ce9ac4ad866750a4386c4f15e800a3073e
Reviewed-on: https://chromium-review.googlesource.com/530063
Commit-Queue: Bjorn Mellem <mellem@webrtc.org>
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Peter Thatcher <pthatcher@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#18636}