chrome/browser/net/chrome_http_user_agent_settings.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_NET_CHROME_HTTP_USER_AGENT_SETTINGS_H_
#define CHROME_BROWSER_NET_CHROME_HTTP_USER_AGENT_SETTINGS_H_

#include <string>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "components/prefs/pref_member.h"
#include "net/url_request/http_user_agent_settings.h"

class PrefService;

// An implementation of |HttpUserAgentSettings| that provides HTTP header
// Accept-Language value that tracks Pref settings.
class ChromeHttpUserAgentSettings : public net::HttpUserAgentSettings {
 public:
  // Must be called on the UI thread.
  explicit ChromeHttpUserAgentSettings(PrefService* prefs);
  // Must be called on the IO thread.
  ~ChromeHttpUserAgentSettings() override;

  // Adds the base language if a corresponding language+region code is present.
  static std::string ExpandLanguageList(const std::string& language_prefs);

  void CleanupOnUIThread();

  // net::HttpUserAgentSettings implementation
  std::string GetAcceptLanguage() const override;
  std::string GetUserAgent() const override;

 private:
  StringPrefMember pref_accept_language_;

  // Avoid re-processing by caching the last value from the preferences and the
  // last result of processing via net::HttpUtil::GenerateAccept*Header().
  mutable std::string last_pref_accept_language_;
  mutable std::string last_http_accept_language_;

  DISALLOW_COPY_AND_ASSIGN(ChromeHttpUserAgentSettings);
};

#endif  // CHROME_BROWSER_NET_CHROME_HTTP_USER_AGENT_SETTINGS_H_