chromeos: Fix shelf appearing at login screen under mash

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

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl.h"
 
 #include <stddef.h>
 
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/shelf/app_list_button.h"
@@ skipping 174 matching lines @@
 
 class LauncherPlatformAppBrowserTest
     : public extensions::PlatformAppBrowserTest {
  protected:
   LauncherPlatformAppBrowserTest() : controller_(nullptr) {}
 
   ~LauncherPlatformAppBrowserTest() override {}
 
   void RunTestOnMainThreadLoop() override {
     controller_ = GetChromeLauncherControllerImpl();
+    ASSERT_TRUE(controller_);
     return extensions::PlatformAppBrowserTest::RunTestOnMainThreadLoop();
   }
 
   ash::ShelfModel* shelf_model() { return ash::WmShell::Get()->shelf_model(); }
 
   ash::ShelfID CreateAppShortcutLauncherItem(
       const ash::launcher::AppLauncherId& app_launcher_id) {
     return controller_->CreateAppShortcutLauncherItem(
         app_launcher_id, shelf_model()->item_count());
   }
@@ skipping 50 matching lines @@
   ShelfAppBrowserTest() : shelf_(NULL), model_(NULL), controller_(NULL) {
   }
 
   ~ShelfAppBrowserTest() override {}
 
   void RunTestOnMainThreadLoop() override {
     shelf_ =
         ash::WmShelf::ForWindow(ash::WmShell::Get()->GetPrimaryRootWindow());
     model_ = ash::WmShell::Get()->shelf_model();
     controller_ = GetChromeLauncherControllerImpl();
+    ASSERT_TRUE(controller_);
     return ExtensionBrowserTest::RunTestOnMainThreadLoop();
   }
 
   size_t NumberOfDetectedLauncherBrowsers(bool show_all_tabs) {
     LauncherItemController* item_controller =
       controller_->GetBrowserShortcutLauncherItemController();
     int items = item_controller->GetApplicationList(
         show_all_tabs ? ui::EF_SHIFT_DOWN : 0).size();
     // If we have at least one item, we have also a title which we remove here.
     return items ? (items - 1) : 0;
@@ skipping 2142 matching lines @@
 
   // Close all windows via the menu item.
   CloseBrowserWindow(browser(), menu1.get(), LauncherContextMenu::MENU_CLOSE);
   EXPECT_EQ(0u, BrowserList::GetInstance()->size());
 
   // Check if "Close" is removed from the context menu.
   std::unique_ptr<LauncherContextMenu> menu2 = CreateBrowserItemContextMenu();
   ASSERT_FALSE(
       IsItemPresentInMenu(menu2.get(), LauncherContextMenu::MENU_CLOSE));
 }