Use ChromeLauncherControllerImpl::GetItem; cleanup.

chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc

Index: chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
diff --git a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
index d4156922efdd0469185a87cffdd56f9417d617ae..515e5ac47b28491ed5331a44662119af579587fb 100644
--- a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
+++ b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
@@ -69,10 +69,10 @@ ash::ShelfID ChromeLauncherControllerMus::CreateAppLauncherItem(
   return ash::TYPE_UNDEFINED;
 }
 
-const ash::ShelfItem& ChromeLauncherControllerMus::GetItem(
+const ash::ShelfItem* ChromeLauncherControllerMus::GetItem(
     ash::ShelfID id) const {
   NOTIMPLEMENTED();
-  return fake_item_;
+  return nullptr;
 }
 
 void ChromeLauncherControllerMus::SetItemType(ash::ShelfID id,