Do not use overlays when VR shell is enabled.

chrome/android/java/src/org/chromium/chrome/browser/fullscreen/ChromeFullscreenManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/fullscreen/ChromeFullscreenManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/fullscreen/ChromeFullscreenManager.java b/chrome/android/java/src/org/chromium/chrome/browser/fullscreen/ChromeFullscreenManager.java
index eb141802101afebf37623e4ec6f7e6ed0f6e645d..aa66e1f8f3534f6e57eb81b47c18fe07db0589cc 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/fullscreen/ChromeFullscreenManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/fullscreen/ChromeFullscreenManager.java
@@ -26,6 +26,7 @@ import org.chromium.base.ApplicationStatus;
 import org.chromium.base.ApplicationStatus.ActivityStateListener;
 import org.chromium.base.BaseChromiumApplication;
 import org.chromium.base.BaseChromiumApplication.WindowFocusChangedListener;
+import org.chromium.base.Log;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.TraceEvent;
 import org.chromium.base.VisibleForTesting;
@@ -396,8 +397,10 @@ public class ChromeFullscreenManager
     @Override
     public void setOverlayVideoMode(boolean enabled) {
         super.setOverlayVideoMode(enabled);
+        Log.d("amp_log", "setOverlayVideoMode");
 
         for (int i = 0; i < mListeners.size(); i++) {
+            Log.d("amp_log", "notifying overlay listener: " + mListeners.get(i));
             mListeners.get(i).onToggleOverlayVideoMode(enabled);
         }
     }