Add VR gradient and grid background to non-WebVR scene.

chrome/browser/android/vr_shell/ui_scene_manager.h

Index: chrome/browser/android/vr_shell/ui_scene_manager.h
diff --git a/chrome/browser/android/vr_shell/ui_scene_manager.h b/chrome/browser/android/vr_shell/ui_scene_manager.h
index 62f2f98ac8e0917278ecbe0a448faec751968b12..72a8ab30d796209265422741e82c0f0eec044be8 100644
--- a/chrome/browser/android/vr_shell/ui_scene_manager.h
+++ b/chrome/browser/android/vr_shell/ui_scene_manager.h
@@ -26,9 +26,13 @@ class UiSceneManager {
   void SetWebVRMode(bool web_vr);
 
  private:
+  void CreateSecurityWarnings();
+  void CreateContentQuad();
+  void CreateBackground();
+
   void ConfigureSecurityWarnings();
   void OnSecurityWarningTimer();
-  void OnGLInitialized();
+  int AllocateId();
 
   UiScene* scene_;
 
@@ -40,6 +44,10 @@ class UiSceneManager {
   bool web_vr_mode_ = false;
   bool secure_origin_ = false;
 
+  int next_available_id_ = 1;
+
+  std::vector<UiElement*> browser_ui_elements_;
+
   base::OneShotTimer security_warning_timer_;
 
   base::WeakPtrFactory<UiSceneManager> weak_ptr_factory_;