Add a browser test for the views external protocol dialog.

chrome/browser/ui/views/external_protocol_dialog.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 CHROME_BROWSER_UI_VIEWS_EXTERNAL_PROTOCOL_DIALOG_H_
 #define CHROME_BROWSER_UI_VIEWS_EXTERNAL_PROTOCOL_DIALOG_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "ui/views/window/dialog_delegate.h"
 #include "url/gurl.h"
 
 class ProtocolDialogDelegate;
 
+namespace test {
+class ExternalProtocolDialogTestApi;
+}
+
 namespace views {
 class MessageBoxView;
 }
 
 class ExternalProtocolDialog : public views::DialogDelegate {
  public:
   // RunExternalProtocolDialog calls this private constructor.
   ExternalProtocolDialog(std::unique_ptr<const ProtocolDialogDelegate> delegate,
                          int render_process_host_id,
                          int routing_id);
 
   ~ExternalProtocolDialog() override;
 
   // views::DialogDelegate methods:
   int GetDefaultDialogButton() const override;
   base::string16 GetDialogButtonLabel(ui::DialogButton button) const override;
   base::string16 GetWindowTitle() const override;
   void DeleteDelegate() override;
   bool Cancel() override;
   bool Accept() override;
   bool Close() override;
   views::View* GetContentsView() override;
   views::Widget* GetWidget() override;
   const views::Widget* GetWidget() const override;
   ui::ModalType GetModalType() const override;
 
  private:
+  friend class test::ExternalProtocolDialogTestApi;
+
   const std::unique_ptr<const ProtocolDialogDelegate> delegate_;
 
   // The message box view whose commands we handle.
   views::MessageBoxView* message_box_view_;
 
   // IDs of the associated WebContents.
   int render_process_host_id_;
   int routing_id_;
 
   // The time at which this dialog was created.
   base::TimeTicks creation_time_;
 
   DISALLOW_COPY_AND_ASSIGN(ExternalProtocolDialog);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_EXTERNAL_PROTOCOL_DIALOG_H_