chromeos: Makes AshTestBase/Helper target mash when appropriate

ash/mus/test/wm_test_helper.cc

 // Copyright 2016 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 "ash/mus/test/wm_test_helper.h"
 
 #include "ash/common/test/wm_shell_test_api.h"
 #include "ash/common/wm_shell.h"
 #include "ash/common/wm_window.h"
 #include "ash/mus/screen_mus.h"
@@ skipping 66 matching lines @@
   window_manager_app_.reset();
 
   base::RunLoop().RunUntilIdle();
   blocking_pool_owner_.reset();
   base::RunLoop().RunUntilIdle();
 
   ui::test::MaterialDesignControllerTestAPI::Uninitialize();
 }
 
 void WmTestHelper::Init() {
+  // MaterialDesignController may have already been initialized. To cover that
+  // case explicitly uninitialize before initializing.
+  ui::test::MaterialDesignControllerTestAPI::Uninitialize();
   ui::MaterialDesignController::Initialize();
 
   views_delegate_ = base::MakeUnique<views::TestViewsDelegate>();
 
   window_manager_app_ = base::MakeUnique<WindowManagerApplication>();
 
   message_loop_.reset(new base::MessageLoopForUI());
 
   const size_t kMaxNumberThreads = 3u;  // Matches that of content.
   const char kThreadNamePrefix[] = "MashBlockingForTesting";
@@ skipping 85 matching lines @@
   const bool is_primary =
       screen->display_list().FindDisplayById(updated_display.id()) ==
       screen->display_list().GetPrimaryDisplayIterator();
   screen->display_list().UpdateDisplay(
       updated_display, is_primary ? display::DisplayList::Type::PRIMARY
                                   : display::DisplayList::Type::NOT_PRIMARY);
 }
 
 }  // namespace mus
 }  // namespace ash