Remove enable_webrtc and treat it as always true from now on.

enable_webrtc=false has been broken for months and no one has noticed,
so let's get rid of this complexity. WebRTC will now be a part of
Chromium until the serpent Nidhoggr ascends into the sky and ushers
in Ragnarök.

Next step: remove #ifdef'd code that depends on defines that
were set by enable_webrtc.

Bug: chromium:800653
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I1661fc56b8005fdae92c3441bb9d7204944bd7c5
Reviewed-on: https://chromium-review.googlesource.com/1044220
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Patrik Höglund <phoglund@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556420}
31 files changed