Out-of-process WebGL needs GfxInfo to exist in the composition
process (which is the GPU process if it exists and the parent process
otherwise). This patch enables the Linux version of that component in
the GPU process; the IPC currently used to give content processes copies
of the parent's GPU info is extended to also send it to the GPU process.
Differential Revision: https://phabricator.services.mozilla.com/D85443
