Provide URL-related info to the VR HTML UI.

chrome/browser/android/vr_shell/vr_shell.h

Index: chrome/browser/android/vr_shell/vr_shell.h
diff --git a/chrome/browser/android/vr_shell/vr_shell.h b/chrome/browser/android/vr_shell/vr_shell.h
index d46eeffc1f1231f4a08e4b54d067ba8f5daf0e18..85bdb756a76fc650083ed59eb18137d215e43d42 100644
--- a/chrome/browser/android/vr_shell/vr_shell.h
+++ b/chrome/browser/android/vr_shell/vr_shell.h
@@ -35,6 +35,7 @@ class VrController;
 class VrInputManager;
 class VrShellDelegate;
 class VrShellRenderer;
+class VrWebContentsObserver;
 struct ContentRectangle;
 struct VrGesture;
 
@@ -151,6 +152,7 @@ class VrShell : public device::GvrDelegate {
   content::WebContents* main_contents_;
   std::unique_ptr<VrCompositor> ui_compositor_;
   content::WebContents* ui_contents_;
+  std::unique_ptr<VrWebContentsObserver> vr_web_contents_observer_;
 
   VrShellDelegate* delegate_ = nullptr;
   std::unique_ptr<VrShellRenderer> vr_shell_renderer_;