Gut ash::MaterialDesignController, and remove the about:flags entry.

ash/test/ash_test_base.h

 // Copyright (c) 2012 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.
 
 #ifndef ASH_TEST_ASH_TEST_BASE_H_
 #define ASH_TEST_ASH_TEST_BASE_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 
-#include "ash/common/material_design/material_design_controller.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/threading/thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/display/display.h"
 #include "ui/wm/public/window_types.h"
 
 namespace aura {
 class Window;
@@ skipping 109 matching lines @@
   };
 
   // Returns the rotation currentl active for the display |id|.
   static display::Display::Rotation GetActiveDisplayRotation(int64_t id);
 
   // Returns the rotation currently active for the internal display.
   static display::Display::Rotation GetCurrentInternalDisplayRotation();
 
   void set_start_session(bool start_session) { start_session_ = start_session; }
 
-  // Sets material mode for the test. This will override material mode set via
-  // command line switches.
-  void set_material_mode(MaterialDesignController::Mode material_mode) {
-    CHECK(!setup_called_);
-    material_mode_ = material_mode;
-  }
-
   AshTestHelper* ash_test_helper() { return ash_test_helper_.get(); }
 
   void RunAllPendingInMessageLoop();
 
   TestScreenshotDelegate* GetScreenshotDelegate();
 
   TestSystemTrayDelegate* GetSystemTrayDelegate();
 
   // Utility methods to emulate user logged in or not, session started or not
   // and user able to lock screen or not cases.
@@ skipping 16 matching lines @@
   // Swap the primary display with the secondary.
   void SwapPrimaryDisplay();
 
  private:
   friend class ash::AshTestImplAura;
 
   bool setup_called_;
   bool teardown_called_;
   // |SetUp()| doesn't activate session if this is set to false.
   bool start_session_;
-  MaterialDesignController::Mode material_mode_;
   std::unique_ptr<AshTestEnvironment> ash_test_environment_;
   std::unique_ptr<AshTestHelper> ash_test_helper_;
   std::unique_ptr<ui::test::EventGenerator> event_generator_;
 
   DISALLOW_COPY_AND_ASSIGN(AshTestBase);
 };
 
 class NoSessionAshTestBase : public AshTestBase {
  public:
   NoSessionAshTestBase() { set_start_session(false); }
   ~NoSessionAshTestBase() override {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NoSessionAshTestBase);
 };
 
 }  // namespace test
 }  // namespace ash
 
 #endif  // ASH_TEST_ASH_TEST_BASE_H_