Add a regression test for the CardUnmaskPrompt.

chrome/browser/ui/autofill/card_unmask_prompt_view.h

 // Copyright 2014 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_AUTOFILL_CARD_UNMASK_PROMPT_VIEW_H_
 #define CHROME_BROWSER_UI_AUTOFILL_CARD_UNMASK_PROMPT_VIEW_H_
 
+#include "base/strings/string16.h"
+
 namespace autofill {
 
 class CardUnmaskPromptController;
 
 // The cross-platform UI interface which prompts the user to unlock a masked
 // Wallet instrument (credit card). This object is responsible for its own
 // lifetime.
 class CardUnmaskPromptView {
  public:
   static CardUnmaskPromptView* CreateAndShow(
       CardUnmaskPromptController* controller);
 
   virtual void ControllerGone() = 0;
   virtual void DisableAndWaitForVerification() = 0;
   virtual void GotVerificationResult(const base::string16& error_message,
                                      bool allow_retry) = 0;
 
  protected:
   CardUnmaskPromptView() {}
   virtual ~CardUnmaskPromptView() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CardUnmaskPromptView);
 };
 
 }  // namespace autofill
 
 #endif  // CHROME_BROWSER_UI_AUTOFILL_CARD_UNMASK_PROMPT_VIEW_H_