Reland "[vr] On-demand install VR DFM on N+"

This is a reland of 3e6d27f2d89227b59b81f75cb3a396a01512595c with fix for
x86 builders (which have VR disabled).

Original change's description:
> [vr] On-demand install VR DFM on N+
>
> This requires handling the case when Chrome is started from VR before
> the module is installed. For this, move code that is required to
> identify VR intents and prevent 2D UI showing up in headset back to the
> base module. Furthermore, request VR module install when entering Chrome
> from VR and set up VR appropriately once the module install was
> successful. If the module cannot be installed within a timeout (we need
> a timeout so that Daydream does not kick us out of VR because we don't
> active VR mode in time) close Chrome on smartphones or launch it in
> 2D-in-VR mode on standalones.
>
> NOTE: The VR DFM is still not activated in Monochrome. So, this change
> won't be active yet.
>
> Bug: 914494
> Change-Id: If37544f3a35b4d01ac924ee874618348d4b6004d
> Reviewed-on: https://chromium-review.googlesource.com/c/1372227
> Reviewed-by: agrieve <agrieve@chromium.org>
> Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
> Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#616442}

TBR=agrieve@chromium.org,mthiesse@chromium.org

Bug: 914494
Change-Id: I4be696bf60e61e57d3d405e9a594838157244abd
Reviewed-on: https://chromium-review.googlesource.com/c/1377427
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616763}
19 files changed