Don't dispatch vrdisplayactivate event if the page that listens for it is invisible

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.vr_shell;
 
 import android.app.Activity;
 import android.app.PendingIntent;
 import android.content.ComponentName;
 import android.content.Intent;
@@ skipping 65 matching lines @@
     }
 
     @Override
     public Boolean isDaydreamCurrentViewer() {
         DaydreamApi daydreamApi = DaydreamApi.create(mActivity);
         if (daydreamApi == null) return false;
         int type = daydreamApi.getCurrentViewerType();
         daydreamApi.close();
         return type == GvrApi.ViewerType.DAYDREAM;
     }
+
+    @Override
+    public void launchVrHomescreen() {
+        DaydreamApi daydreamApi = DaydreamApi.create(mActivity);
+        if (daydreamApi == null) return;
+        daydreamApi.launchVrHomescreen();
+        daydreamApi.close();
+    }
 }