Dynamic resolution change for VP8 HW encode.

Off by default for now.

BUG=
R=glaznev@webrtc.org, stefan@webrtc.org
TBR=mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/45849004

Cr-Original-Commit-Position: refs/heads/master@{#9045}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 61b4d518af7c2e4156056931d3512a49032b827d
16 files changed