The files that are built when use_gtk==1 are not included in the Chromium build
(webrtc/media/devices/gtkvideorenderer.cc and webrtc/media/devices/gtkvideorenderer.h)
so to preserve previous behavior in Chromium before/after
https://codereview.webrtc.org/1587193006, this is the right thing to do.
The reason this was discovered was that a Chrome OS build started failing, since
it was lacking the gtk+2.0 package.
NOTRY=True
BUG=chromium:584722
TBR=tommi@webrtc.org
Review URL: https://codereview.webrtc.org/1677693002
Cr-Commit-Position: refs/heads/master@{#11510}