Stay in VR while showing DOFF flow and connect CCT exit button to this.

chrome/browser/android/vr_shell/ui_scene_manager.cc

Index: chrome/browser/android/vr_shell/ui_scene_manager.cc
diff --git a/chrome/browser/android/vr_shell/ui_scene_manager.cc b/chrome/browser/android/vr_shell/ui_scene_manager.cc
index 26de8a498a1791632fc8ca727d7f76274fc6fac4..4f6ed3117db1cda080a5477d9aad26cb30af76f5 100644
--- a/chrome/browser/android/vr_shell/ui_scene_manager.cc
+++ b/chrome/browser/android/vr_shell/ui_scene_manager.cc
@@ -415,7 +415,9 @@ void UiSceneManager::SetIsExiting() {
 void UiSceneManager::SetHistoryButtonsEnabled(bool can_go_back,
                                               bool can_go_forward) {}
 
-void UiSceneManager::OnCloseButtonClicked() {}
+void UiSceneManager::OnCloseButtonClicked() {
+  browser_->ExitCct();
+}
 
 int UiSceneManager::AllocateId() {
   return next_available_id_++;