components: Cleanup class/struct fwd declarations

components/app_modal/views/javascript_app_modal_dialog_views.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 COMPONENTS_APP_MODAL_VIEWS_JAVASCRIPT_APP_MODAL_DIALOG_VIEWS_H_
 #define COMPONENTS_APP_MODAL_VIEWS_JAVASCRIPT_APP_MODAL_DIALOG_VIEWS_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/app_modal/native_app_modal_dialog.h"
 #include "ui/views/window/dialog_delegate.h"
 
-class JavaScriptAppModalDialog;
-
 namespace views {
 class MessageBoxView;
 }
 
 namespace app_modal {
 
+class JavaScriptAppModalDialog;
+
 class JavaScriptAppModalDialogViews : public NativeAppModalDialog,
                                       public views::DialogDelegate {
  public:
   explicit JavaScriptAppModalDialogViews(JavaScriptAppModalDialog* parent);
   ~JavaScriptAppModalDialogViews() override;
 
   // Overridden from NativeAppModalDialog:
   int GetAppModalDialogButtons() const override;
   void ShowAppModalDialog() override;
   void ActivateAppModalDialog() override;
@@ skipping 25 matching lines @@
 
   // The message box view whose commands we handle.
   views::MessageBoxView* message_box_view_;
 
   DISALLOW_COPY_AND_ASSIGN(JavaScriptAppModalDialogViews);
 };
 
 }  // namespace app_modal
 
 #endif  // COMPONENTS_APP_MODAL_VIEWS_JAVASCRIPT_APP_MODAL_DIALOG_VIEWS_H_