WebXR has a feature that allows users to request a framebuffer scalar to indicate the quality they want for the allocated buffer. (1.0 == 1:1 native resolution, 0.5 == half that, 0.0 == use the system recommendation.)
At the moment that feature is not functioning as well as it could because the VR service only communicates the recommended framebuffer size, which on mobile is significantly lower than the native size. The implementation should be updated to report both the native size and the recommended scalar so that WebXR implementations can perform more accurately.
Comment 1 by bugdroid1@chromium.org
, Apr 6 2018