Patch that caused this: https://chromium-review.googlesource.com/c/chromium/src/+/675788

Fix is in progress.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5890b651419a4f51a89a474ff6409146ce44d207

commit 5890b651419a4f51a89a474ff6409146ce44d207
Author: Yash Malik <ymalik@google.com>
Date: Thu Sep 21 22:19:07 2017

[vr] Fix splash screen shown for auto-present intents

This regressed in https://chromium-review.googlesource.com/675788.

The problem is that the splash screen was a part of the WebVR subtree and we
weren't drawing the WebVR subtree until the site submitted a frame.

This CL moves the splash screen to its own subtree under kRoot and renders it
regardless of being in WebVR mode.

Bug:  767523 
Change-Id: Ib4f7fcef615e479db89ce2c5fb72e894270aa614
Reviewed-on: https://chromium-review.googlesource.com/677225
Reviewed-by: Ian Vollick <vollick@chromium.org>
Commit-Queue: Yash Malik <ymalik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#503581}
[modify] https://crrev.com/5890b651419a4f51a89a474ff6409146ce44d207/chrome/browser/android/vr_shell/vr_shell_gl.cc
[modify] https://crrev.com/5890b651419a4f51a89a474ff6409146ce44d207/chrome/browser/vr/elements/ui_element_name.h
[modify] https://crrev.com/5890b651419a4f51a89a474ff6409146ce44d207/chrome/browser/vr/ui_renderer.cc
[modify] https://crrev.com/5890b651419a4f51a89a474ff6409146ce44d207/chrome/browser/vr/ui_renderer.h
[modify] https://crrev.com/5890b651419a4f51a89a474ff6409146ce44d207/chrome/browser/vr/ui_scene.cc
[modify] https://crrev.com/5890b651419a4f51a89a474ff6409146ce44d207/chrome/browser/vr/ui_scene.h
[modify] https://crrev.com/5890b651419a4f51a89a474ff6409146ce44d207/chrome/browser/vr/ui_scene_manager.cc
[modify] https://crrev.com/5890b651419a4f51a89a474ff6409146ce44d207/chrome/browser/vr/ui_scene_manager.h