Migrate WebVR Cardboard implementation to GVR

BUG=389343

Committed: https://crrev.com/267d5f909f25543d2351cc506626b5d5c08461c3
Review-Url: https://codereview.chromium.org/2219203002
Cr-Original-Commit-Position: refs/heads/master@{#412710}
Cr-Commit-Position: refs/heads/master@{#413217}
25 files changed