Move user_agent code from webkit/ to content/.

content/common/user_agent_internal.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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 WEBKIT_COMMON_USER_AGENT_USER_AGENT_H_
-#define WEBKIT_COMMON_USER_AGENT_USER_AGENT_H_
+#ifndef CONTENT_COMMON_USER_AGENT_INTERNAL_H_
+#define CONTENT_COMMON_USER_AGENT_INTERNAL_H_
 
 #include <string>
 
-#include "base/basictypes.h"
-#include "url/gurl.h"
-#include "webkit/common/user_agent/webkit_user_agent_export.h"
-
-namespace webkit_glue {
+namespace content {
 
 // Sets the user agent.  Pass true for overriding if this is a custom
 // user agent instead of the default one (in order to turn off any browser
 // sniffing workarounds). This must be called before GetUserAgent() can
 // be called.
-WEBKIT_USER_AGENT_EXPORT void SetUserAgent(const std::string& user_agent,
-                                           bool overriding);
+void SetUserAgent(const std::string& user_agent, bool overriding);

[jam, 2014/03/05 00:09:26]

so looking at the callsites for this, I think we can get rid of the non-test one
(SetUpTestEnvironmentForUnitTests() in webkit_support.cc). i.e. move that logic
in content_main_runner.cc to user_agent.cc's GetUserAgent's lazy initialization.
this method will have to remain, but can get a ForTesting suffix, for use by the
webkit_support.cc

 
-// Returns the user agent to use for the given URL. SetUserAgent() must
-// be called prior to calling this function.
-WEBKIT_USER_AGENT_EXPORT const std::string& GetUserAgent(const GURL& url);
+}  // namespace content
 
-}  // namespace webkit_glue
-
-#endif  // WEBKIT_COMMON_USER_AGENT_USER_AGENT_H_
+#endif  // CONTENT_COMMON_USER_AGENT_INTERNAL_H_