Implement new compositor and ContentViewCore reparenting for VR Shell.

chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
index 430315ba541563110d5ccdc95960ea074ee32729..cb45073c93eebbf452db91d41c5fe1196fe04abe 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java
@@ -1602,4 +1602,11 @@ public class ChromeTabbedActivity extends ChromeActivity implements OverviewMode
     public boolean isVrShellEnabled() {
         return mVrShellDelegate.isVrShellEnabled();
     }
+
+    // TODO(mthiesse): Toggle toolbar overlay, popups, etc.
+    public void setUIVisibilityForVR(int visibility) {
+        mControlContainer.setVisibility(visibility);

[Ted C, 2016/09/12 23:33:11]

can your surfaceview sit on top?  do you need to hide the toolbar/etc.. in that
case?  I was under the impression it either needed to be at the very top or very
bottom and we don't really need to overlay any android widgets so the top would
avoid this.

ContentVideoView I "believe" does this.  We should look at what they are doing
at least and see if we can share the same behavior as they should be doing
similar things in my opinion.

[mthiesse, 2016/09/13 14:53:48]

So I've duplicated what ContentVideoView does and I still need to hide the views
in ChromeTabbedActivity. I'm really unclear as to why this is - I think it's an
issue with how GvrLayout adds its views to the view hierarchy, outside of my
control. What I see is the vertical center line for the stereo view sitting on
top of the compositorViewHolder, with the stereo content sitting behind the
compositorViewHolder.

The GvrLayout code is here: https://goto.google.com/gvrlayout-code-location. Are
they doing something incorrectly? Is this a bug in their library? (If so, it
probably won't be fixed any time soon)

[qinmin, 2016/09/14 18:45:24]

CompositorView calls setZOrderMediaOverlay(), so it is behind the window, but
above the ContentVideoView.  So your change is to add a view on top of the
CompositorView and one beneath it, and hide the Compositor View?

+        getCompositorViewHolder().getSurfaceView().setVisibility(visibility);
+        getCompositorViewHolder().setVisibility(visibility);
+    }
 }