Only create QuickAnswersController if the feature is enabled.

Bug: b/156912750
Test: manual test
Change-Id: I4e7c4ee3623499108d8883009f85d94cc6d9d22b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2207950
Commit-Queue: Li Lin <llin@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#770699}

ash/public/cpp/quick_answers_controller.h

@@ -25,6 +25,8 @@ class ASH_PUBLIC_EXPORT QuickAnswersController {
   QuickAnswersController();
   virtual ~QuickAnswersController();
 
+  // Get the instance of |QuickAnswersController|. It is only available when
+  // quick answers rich UI is enabled.
   static QuickAnswersController* Get();
 
   // Passes in a client instance for the controller to use.

ash/shell.cc

@@ -1071,7 +1071,10 @@ void Shell::Init(
   magnification_controller_ = std::make_unique<MagnificationController>();
   mru_window_tracker_ = std::make_unique<MruWindowTracker>();
   assistant_controller_ = std::make_unique<AssistantControllerImpl>();
-  quick_answers_controller_ = std::make_unique<QuickAnswersControllerImpl>();
+  if (chromeos::features::IsQuickAnswersEnabled() &&
+      chromeos::features::IsQuickAnswersRichUiEnabled()) {
+    quick_answers_controller_ = std::make_unique<QuickAnswersControllerImpl>();
+  }
 
   // |assistant_controller_| is put before |ambient_controller_| as it will be
   // used by the latter.

chrome/browser/renderer_context_menu/quick_answers_menu_observer.cc

@@ -78,7 +78,8 @@ QuickAnswersMenuObserver::QuickAnswersMenuObserver(
             .get(),
         assistant_state, /*delegate=*/this);
     quick_answers_controller_ = ash::QuickAnswersController::Get();
-    DCHECK(quick_answers_controller_);
+    if (!quick_answers_controller_)
+      return;
     quick_answers_controller_->SetClient(std::make_unique<QuickAnswersClient>(
         content::BrowserContext::GetDefaultStoragePartition(browser_context)
             ->GetURLLoaderFactoryForBrowserProcess()
@@ -150,6 +151,8 @@ void QuickAnswersMenuObserver::OnContextMenuShown(
 
 void QuickAnswersMenuObserver::OnContextMenuViewBoundsChanged(
     const gfx::Rect& bounds_in_screen) {
+  if (!quick_answers_controller_)
+    return;
   quick_answers_controller_->UpdateQuickAnswersAnchorBounds(bounds_in_screen);
 }