Enable clang warning for ignored attributes.

content/public/browser/presentation_session.h

 // Copyright 2015 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 CONTENT_PUBLIC_BROWSER_PRESENTATION_SESSION_H_
 #define CONTENT_PUBLIC_BROWSER_PRESENTATION_SESSION_H_
 
 #include <string>
 
 #include "content/common/content_export.h"
 
 namespace content {
 
 // Represents a presentation session that has been established via either
 // browser actions or Presentation API.
 struct CONTENT_EXPORT PresentationSessionInfo {
   PresentationSessionInfo(const std::string& presentation_url,
                           const std::string& presentation_id);
   ~PresentationSessionInfo();
 
   const std::string presentation_url;
   const std::string presentation_id;
 };
 
 // Possible reasons why an attempt to create a presentation session failed.
-enum CONTENT_EXPORT PresentationErrorType {
+enum PresentationErrorType {
   PRESENTATION_ERROR_NO_AVAILABLE_SCREENS,
   PRESENTATION_ERROR_SESSION_REQUEST_CANCELLED,
   PRESENTATION_ERROR_NO_PRESENTATION_FOUND,
   PRESENTATION_ERROR_UNKNOWN,
 };
 
 // Struct returned when an attempt to create a presentation session failed.
 struct CONTENT_EXPORT PresentationError {
   PresentationError(PresentationErrorType error_type,
                     const std::string& message);
   ~PresentationError();
 
   const PresentationErrorType error_type;
   const std::string message;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_PRESENTATION_SESSION_H_