Fix some extern usage in .cc files.

content/common/sandbox_init_mac.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 CONTENT_COMMON_SANDBOX_INIT_MAC_H_
 #define CONTENT_COMMON_SANDBOX_INIT_MAC_H_
 
 namespace content {
 
 // Initialize the sandbox for renderer, gpu, utility, worker, and plugin
 // processes, depending on the command line flags. For the browser process which
 // is not sandboxed, this call is a no-op.
 // Returns true if the sandbox was initialized succesfully, false if an error
 // occurred.  If process_type isn't one that needs sandboxing, true is always
 // returned.
 bool InitializeSandbox();
 
-// The bootstrap server name of the real bootstrap port. This is never used
-// with bootstrap_register, but is instead used with a POLICY_SUBSTITUTE_PORT
-// in the bootstrap sandbox. In child processes, the the launchd/bootstrap
-// sandbox will have replaced the bootstrap port with one controlled by the
-// interception server. This server name can be used to request the original
-// server, from the browser, in NPAPI plugins.
-extern const char kBootstrapPortNameForNPAPIPlugins[];
-
 }  // namespace content
 
 #endif  // CONTENT_COMMON_SANDBOX_INIT_MAC_H_