GitLab

exo::Surface wasn't setting the device_scale_factor in CompositorFrames.
This was triggering a DCHECK when the SurfaceInfo for new cc::Surfaces
have device_scale_factor == 0.

BUG=b/37654593

Review-Url: https://codereview.chromium.org/2843723003
Cr-Commit-Position: refs/heads/master@{#468076}