Fix crash when set VR mode to false after VrShell is destroyed

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

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrClassesWrapper.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrClassesBuilder.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrClassesWrapper.java
similarity index 78%
rename from chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrClassesBuilder.java
rename to chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrClassesWrapper.java
index a2c4de721f9c9578fd99c4c1a5fa73448ecdd9eb..4bc683df2b3a12d916c3db22de1dd51630bdd7c5 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrClassesBuilder.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrClassesWrapper.java
@@ -5,10 +5,10 @@
 package org.chromium.chrome.browser.vr_shell;
 
 /**
- * Abstracts away the VrClassesBuilderImpl class, which may or may not be present at runtime
+ * Abstracts away the VrClassesWrapperImpl class, which may or may not be present at runtime
  * depending on compile flags.
  */
-public interface VrClassesBuilder {
+public interface VrClassesWrapper {
     /**
      * Creates a NonPresentingGvrContextImpl instance.
      */
@@ -28,4 +28,9 @@ public interface VrClassesBuilder {
     * Creates a VrCoreVersionCheckerImpl instance.
     */
     public VrCoreVersionChecker createVrCoreVersionChecker();
+
+    /**
+     * Sets VR Mode to |enabled|.
+     */
+    public void setVrModeEnabled(boolean enabled);
 }