Add a flag to make VR compositing happen in a low-integrity AppContainer.

Currently VR APIs on desktop are hosted in an unsandboxed process when enabled. After this
change, VR Apis may be hosted in an AppContainer low-integrity process when a flag is enabled.
This allows debugging sandbox issues before enabling VR by default.

BUG=795510

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:linux_vr;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: Ie16dd86cfa23171b0025359cd7e2d4db7997a9e7
Reviewed-on: https://chromium-review.googlesource.com/1162763
Reviewed-by: Will Harris <[email protected]>
Reviewed-by: John Abd-El-Malek <[email protected]>
Reviewed-by: James Forshaw <[email protected]>
Commit-Queue: Bill Orr <[email protected]>
Cr-Commit-Position: refs/heads/master@{#595657}
15 files changed