The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2dc94cbcc999cade8a3a9a9b2118be81a403e54b

commit 2dc94cbcc999cade8a3a9a9b2118be81a403e54b
Author: mthiesse <mthiesse@chromium.org>
Date: Fri May 19 15:16:57 2017

Stay in VR while showing DOFF flow and connect CCT exit button to this.

This CL does a bunch of complicated things like allowing us to stay in VR when paused as long as we're showing the DOFF flow and expect to return to chrome while still in VR.

There are some gotchas I had to be careful to address, like if the user hits the home button during the DOFF flow then returns to any instance of chrome (CTA/CCT/WebApk) we need to make sure to exit VR in the activity that's still showing the DOFF flow.

This also fixes a possible Activity leak if the nonpresentingdelegate remains alive when switching activities.

BUG= 719661 

Review-Url: https://codereview.chromium.org/2889693005
Cr-Commit-Position: refs/heads/master@{#473193}

[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.cc
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/ui_scene_manager.cc
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/ui_scene_manager_unittest.cc
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/vr_browser_interface.h
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/vr_gl_thread.cc
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/vr_gl_thread.h
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/vr_shell.cc
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/vr_shell.h
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/vr_shell_delegate.cc
[modify] https://crrev.com/2dc94cbcc999cade8a3a9a9b2118be81a403e54b/chrome/browser/android/vr_shell/vr_shell_delegate.h

Adding to MVP-Next for discussion and clarification.

VRB team triage deciding to close because: unclear of next steps.