Add a dialog for getting user consent in the echo redeem flow.

ui/views/controls/styled_label_listener.h

 // Copyright 2013 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_CONTROLS_STYLED_LABEL_LISTENER_H_
 #define UI_VIEWS_CONTROLS_STYLED_LABEL_LISTENER_H_
 
+#include "ui/views/views_export.h"
+
 namespace ui {
 class Range;
 }
 
 namespace views {
 
 // A listener interface for StyledLabel.
 class VIEWS_EXPORT StyledLabelListener {
  public:
   virtual void StyledLabelLinkClicked(const ui::Range& range,
                                       int event_flags) = 0;
 
  protected:
   virtual ~StyledLabelListener() {}
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_STYLED_LABEL_LISTENER_H_