Add primary repo for WebRTC Android factory.
Add primary repo for WebRTC Android factory.

Similar to changes in
http://src.chromium.org/viewvc/chrome?view=rev&revision=221758
this is needed for the WebRTC revision to show
up instead of the Chromium revision in the build listings of
http://build.chromium.org/p/client.webrtc/waterfall

TEST=none
BUG=none

Review URL: https://chromiumcodereview.appspot.com/24315005

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@225022 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build