This is the first step towards getting rid of gflags as a dependency.
It has been causing us extra work for a long time since it's not present
in Chromium as one example.
BUG=webrtc:7644
NOTRY=True
Review-Url: https://codereview.webrtc.org/2874403003
Cr-Commit-Position: refs/heads/master@{#18157}