[reland] Makes MaterialDesignController initialization explicit

ui/base/test/material_design_controller_test_api.h

 // Copyright 2015 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 UI_BASE_TEST_MATERIAL_DESIGN_CONTROLLER_TEST_API_H_
 #define UI_BASE_TEST_MATERIAL_DESIGN_CONTROLLER_TEST_API_H_
 
 #include "base/macros.h"
 #include "ui/base/material_design/material_design_controller.h"
 
 namespace ui {
 namespace test {
 
 // Test API to access the internal state of the MaterialDesignController class.
+// Creating an instance of this class and then destroying it preserves global
+// state in MaterialDesignController class.
 class MaterialDesignControllerTestAPI {
  public:
+  MaterialDesignControllerTestAPI(MaterialDesignController::Mode mode);

[sky, 2016/04/13 23:49:58]

explicit.

[varkha, 2016/04/14 00:03:33]

Done.

+  ~MaterialDesignControllerTestAPI();
+
   // Wrapper functions for MaterialDesignController internal functions.
-  static void SetMode(MaterialDesignController::Mode mode);
-  static void UninitializeMode();
+  static void Uninitialize();
 
  private:
+  MaterialDesignController::Mode previous_mode_;

[sky, 2016/04/13 23:49:58]

nit: const on this and the next.

[varkha, 2016/04/14 00:03:33]

Done.

+  bool previous_initialized_;
+
   DISALLOW_COPY_AND_ASSIGN(MaterialDesignControllerTestAPI);
 };
 
 }  // namespace test
 }  // namespace ui
 
-#endif  // UI_BASE_TEST_MATERIAL_DESIGN_CONTROLLER_TEST_AP_H_
+#endif  // UI_BASE_TEST_MATERIAL_DESIGN_CONTROLLER_TEST_API_H_