Adding support for launching firefox from webrtc.DEPS.

This is required for the firefox interop test being added in

This is only intended to work for Linux for now. We will need some light
redesign to get this to work on Windows as well.

Review URL:

git-svn-id: 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
3 files changed