Don't treat Esc like Cancel in the external protocol dialog on Views.

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"
@@ skipping 15 matching lines @@
 
   ~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:
   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_