The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/300a7753af3fa5557e8724811b7a62fc106d54f4

commit 300a7753af3fa5557e8724811b7a62fc106d54f4
Author: Christopher Grant <cjgrant@chromium.org>
Date: Wed Sep 27 21:11:26 2017

VR: Use correct color format when flushing UI element textures

We have been assuming a platform-specific arrangement of bytes in the
Skia textures we generate.  The resulting SkPixmap color format varies
by platform, and is different on Linux vs. Android.

BUG= 769325 

Change-Id: Id157f45b179fa74478b1662e7ada3b2e8ff82456
Reviewed-on: https://chromium-review.googlesource.com/688334
Reviewed-by: Yash Malik <ymalik@chromium.org>
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#504769}
[modify] https://crrev.com/300a7753af3fa5557e8724811b7a62fc106d54f4/chrome/browser/vr/elements/textured_element.cc
[modify] https://crrev.com/300a7753af3fa5557e8724811b7a62fc106d54f4/chrome/browser/vr/vr_shell_renderer.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc

commit 16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc
Author: Christopher Grant <cjgrant@chromium.org>
Date: Fri Sep 29 02:12:13 2017

VR: Add a Linux-based VR UI testapp

This app draws the VR UI in a window on Linux, using fake browser
state.  This lets us debug UI appearance and implementation without
building and loading the full Android APK.

BUG= 769325 

Change-Id: I1a0efd7376d5103ed98641587f559ba8a5f65450
Reviewed-on: https://chromium-review.googlesource.com/682754
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Reviewed-by: Michael Spang <spang@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505254}
[modify] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/BUILD.gn
[add] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/testapp/BUILD.gn
[add] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/testapp/DEPS
[add] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/testapp/gl_renderer.cc
[add] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/testapp/gl_renderer.h
[add] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/testapp/vr_test_context.cc
[add] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/testapp/vr_test_context.h
[add] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/testapp/vr_testapp.cc
[modify] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/ui.cc
[modify] https://crrev.com/16c6f4e2d6f52a269e823c389aaaeb0a4d78d4cc/chrome/browser/vr/ui_renderer.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/40312cd2624446fa4c62406e66ff7490b3ec7ad0

commit 40312cd2624446fa4c62406e66ff7490b3ec7ad0
Author: Christopher Grant <cjgrant@chromium.org>
Date: Mon Oct 02 14:47:20 2017

VR: Disable subpixel rendering when rendering UI text

Subpixel rendering is enabled by default on (at least) Linux. In VR,
where we're rendering textures that are re-rendered and distorted,
subpixel rendering is not useful. Rather, on a transparent background,
it inteferes with text rendering (as is visible in the UI test app).

BUG= 769325 

Change-Id: I8db5a3a6cec7376c5344418b5c6e49c23fb224ea
Reviewed-on: https://chromium-review.googlesource.com/688044
Reviewed-by: Ian Vollick <vollick@chromium.org>
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505608}
[modify] https://crrev.com/40312cd2624446fa4c62406e66ff7490b3ec7ad0/chrome/browser/vr/elements/ui_texture.cc
[modify] https://crrev.com/40312cd2624446fa4c62406e66ff7490b3ec7ad0/chrome/browser/vr/elements/ui_texture.h
[modify] https://crrev.com/40312cd2624446fa4c62406e66ff7490b3ec7ad0/chrome/browser/vr/elements/url_bar_texture.cc
[modify] https://crrev.com/40312cd2624446fa4c62406e66ff7490b3ec7ad0/chrome/browser/vr/elements/webvr_url_toast_texture.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2f9e623f9ba40b906afaa512df6a44ba9abf0b20

commit 2f9e623f9ba40b906afaa512df6a44ba9abf0b20
Author: Christopher Grant <cjgrant@chromium.org>
Date: Mon Oct 02 17:59:37 2017

VR: Add head pose and similar support to testapp

- Mouse movement with the right mouse button down moves the head.
- Laser moves relative to the head position.
- Escape resets the view.
- Mouse wheel zooms the view in and out (ie. examine textures).
- Keys F and I toggle fullscreen and incognito mode.

BUG= 769325 

Change-Id: Ib902c491e91b3607c90a13535b326fabb3e3c878
Reviewed-on: https://chromium-review.googlesource.com/693143
Commit-Queue: Christopher Grant <cjgrant@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505673}
[modify] https://crrev.com/2f9e623f9ba40b906afaa512df6a44ba9abf0b20/chrome/browser/vr/testapp/vr_test_context.cc
[modify] https://crrev.com/2f9e623f9ba40b906afaa512df6a44ba9abf0b20/chrome/browser/vr/testapp/vr_test_context.h

The basic app has landed.  To use it:

gn gen --args='target_os="linux" use_ozone=true use_goma=true is_component_build=true enable_vr=true' out/vr-ui-testapp

nice ninja -C out/vr-ui-testapp -j500 -l32 vr_testapp

out/vr-ui-testapp/vr_testapp