Remove an unneeded forward declaration.

chrome/browser/extensions/api/cryptotoken_private/cryptotoken_private_api.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_EXTENSIONS_API_CRYPTOTOKEN_PRIVATE_CRYPTOTOKEN_PRIVATE_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_CRYPTOTOKEN_PRIVATE_CRYPTOTOKEN_PRIVATE_API_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/extensions/chrome_extension_function_details.h"
 #include "chrome/common/extensions/api/cryptotoken_private.h"
 #include "extensions/browser/extension_function.h"
 
 // Implementations for chrome.cryptotokenPrivate API functions.
 
-namespace infobars {
-class InfoBar;
-}
-
 namespace extensions {
 namespace api {
 
 class CryptotokenPrivateCanOriginAssertAppIdFunction
     : public UIThreadExtensionFunction {
   public:
     CryptotokenPrivateCanOriginAssertAppIdFunction();
     DECLARE_EXTENSION_FUNCTION("cryptotokenPrivate.canOriginAssertAppId",
                                CRYPTOTOKENPRIVATE_CANORIGINASSERTAPPID)
   protected:
     ~CryptotokenPrivateCanOriginAssertAppIdFunction() override {}
     ResponseAction Run() override;
 
   private:
     ChromeExtensionFunctionDetails chrome_details_;
 };
 
 }  // namespace api
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_CRYPTOTOKEN_PRIVATE_CRYPTOTOKEN_PRIVATE_API_H_