Refactor ViewsDelegate singleton

ui/views/test/views_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 UI_VIEWS_TEST_VIEWS_TEST_BASE_H_
 #define UI_VIEWS_TEST_VIEWS_TEST_BASE_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 #include "ui/views/test/test_views_delegate.h"
+#include "ui/views/widget/widget.h"
 
 #if defined(OS_WIN)
 #include "ui/base/win/scoped_ole_initializer.h"
 #endif
 
 namespace views {
 
 class ViewsTestHelper;
 
 // A base class for views unit test. It creates a message loop necessary
 // to drive UI events and takes care of OLE initialization for windows.
 class ViewsTestBase : public PlatformTest {
  public:
   ViewsTestBase();
   ~ViewsTestBase() override;
 
   // testing::Test:
   void SetUp() override;
   void TearDown() override;
 
   void RunPendingMessages();
 
   // Creates a widget of |type| with any platform specific data for use in
   // cross-platform tests.
   Widget::InitParams CreateParams(Widget::InitParams::Type type);
 
  protected:
-  TestViewsDelegate& views_delegate() const { return *views_delegate_.get(); }
+  TestViewsDelegate* views_delegate() const { return views_delegate_.get(); }
 
-  void set_views_delegate(TestViewsDelegate* views_delegate) {
-    views_delegate_.reset(views_delegate);
+  void set_views_delegate(scoped_ptr<TestViewsDelegate> views_delegate) {
+    views_delegate_.swap(views_delegate);
   }
 
   base::MessageLoopForUI* message_loop() { return &message_loop_; }
 
   // Returns a context view. In aura builds, this will be the
   // RootWindow. Everywhere else, NULL.
   gfx::NativeWindow GetContext();
 
  private:
   base::MessageLoopForUI message_loop_;
   scoped_ptr<TestViewsDelegate> views_delegate_;
   scoped_ptr<ViewsTestHelper> test_helper_;
   bool setup_called_;
   bool teardown_called_;
 
 #if defined(OS_WIN)
   ui::ScopedOleInitializer ole_initializer_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(ViewsTestBase);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_TEST_VIEWS_TEST_BASE_H_