Notify VRDeviceProviders when there are pages listening for vrdisplayactivate

chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
index ed98793eb158000bb485305bc3d2d4ab7ca7c919..5eae53af461b4953e6dd818f95b0c6636a10e0cf 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
@@ -83,6 +83,7 @@ public class VrShellDelegate {
     private Tab mTab;
     private boolean mRequestedWebVR;
     private long mLastVRExit;
+    private boolean mListeningForWebVrActivate;
 
     public VrShellDelegate(ChromeTabbedActivity activity) {
         mActivity = activity;
@@ -387,6 +388,11 @@ public class VrShellDelegate {
         mNonPresentingGvrContext = null;
     }
 
+    @CalledByNative
+    private void setListeningForWebVrActivate(boolean listening) {
+        mListeningForWebVrActivate = listening;
+    }
+
     /**
      * Exits VR Shell, performing all necessary cleanup.
      */