Decouple VR Shell DPR and CSS size from Physical Displays.
This CL introduces two virtual displays for VR Shell, one for the content window, and one for the background UI window (which is made as small as possible to save on memory).
The UI now dynamically controls its size, and the content defaults to a reasonable size regular web browsing (in VR).
BUG=643480
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
Review-Url: https://codereview.chromium.org/2428383006
Cr-Commit-Position: refs/heads/master@{#435702}
17 files changed
