Refactor Vr activity into ChromeTabbedActivity.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellInterface.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellInterface.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellInterface.java
new file mode 100644
index 0000000000000000000000000000000000000000..f2235389431577e8afad32cf9b16bffca6dff2a4
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellInterface.java
@@ -0,0 +1,36 @@
+// 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;
+
+/**
+ * Abstracts away the VrShell class, which may or may not be present at runtime depending on
+ * compile flags.
+ */
+public abstract interface VrShellInterface {
+    /**
+     * Performs native VrShell initialization.
+     */
+    public abstract void onNativeLibraryReady();
+
+    /**
+     * Pauses VrShell.
+     */
+    public abstract void pause();
+
+    /**
+     * Resumes VrShell.
+     */
+    public abstract void resume();
+
+    /**
+     * Destroys VrShell.
+     */
+    public abstract void teardown();
+
+    /**
+     * Sets Android VR Mode to |enabled|.
+     */
+    public abstract void setVrModeEnabled(boolean enabled);
+}