Provide mutable members of UrlRequestContext via pure-virtual interface

net/url_request/const_http_accept_language_and_charset.h

Index: net/url_request/const_http_accept_language_and_charset.h
diff --git a/net/url_request/const_http_accept_language_and_charset.h b/net/url_request/const_http_accept_language_and_charset.h
new file mode 100644
index 0000000000000000000000000000000000000000..0146ea4c668e6296cca64f850b6bb3d2c5c04202
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+++ b/net/url_request/const_http_accept_language_and_charset.h
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+// 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 NET_URL_REQUEST_CONST_HTTP_ACCEPT_LANGUAGE_AND_CHARSET_H_
+#define NET_URL_REQUEST_CONST_HTTP_ACCEPT_LANGUAGE_AND_CHARSET_H_
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "net/url_request/http_user_agent_settings.h"
+
+namespace net {
+
+// A partial implementation of |HttpUserAgentSettings| that always provides
+// the same constant values for the HTTP Accept-Language and Accept-Charset
+// headers.  Implementors can inherit from this class and implement
+// |GetUserAgent()|.
+class NET_EXPORT ConstHttpAcceptLanguageAndCharset
+    : public HttpUserAgentSettings {
+ public:
+  // HttpUserAgentSettings implementation
+  virtual std::string GetAcceptLanguage() OVERRIDE;
+  virtual std::string GetAcceptCharset() OVERRIDE;
+
+ protected:
+  ConstHttpAcceptLanguageAndCharset(const std::string& accept_language,
+                                    const std::string& accept_charset);
+  virtual ~ConstHttpAcceptLanguageAndCharset() {}
+
+ private:
+  const std::string accept_language_;
+  const std::string accept_charset_;
+
+  DISALLOW_COPY_AND_ASSIGN(ConstHttpAcceptLanguageAndCharset);
+};
+
+}  // namespace net
+
+#endif  // NET_URL_REQUEST_CONST_HTTP_ACCEPT_LANGUAGE_AND_CHARSET_H_
+