Remove ENABLE_VR_SHELL compile-time define.

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 81c0ed93a506f108f34cc22ca34ea0ce49e6fb75..f60efc718e59a97027a864a6d4a14a466e853ced 100644
--- a/chrome/browser/android/vr_shell/vr_shell.h
+++ b/chrome/browser/android/vr_shell/vr_shell.h
@@ -173,7 +173,7 @@ class VrShell : public device::GvrDelegate, content::WebContentsObserver {
                                 const gvr::Rectf& right_bounds) override;
   void OnVRVsyncProviderRequest(
       device::mojom::VRVSyncProviderRequest request) override;
-  void UpdateVSyncInterval(long timebase_nanos,
+  void UpdateVSyncInterval(int64_t timebase_nanos,
                            double interval_seconds) override;
   bool SupportsPresentation() override;
   void ResetPose() override;
@@ -183,6 +183,8 @@ class VrShell : public device::GvrDelegate, content::WebContentsObserver {
 
   void ProcessTabArray(JNIEnv* env, jobjectArray tabs, bool incognito);
 
+  bool vr_shell_enabled_;
+
   std::unique_ptr<UiInterface> html_interface_;
   bool content_paused_ = false;
   bool webvr_mode_ = false;