In preparation for becoming an internal plugin in chrome I did these things:...

plugin/mac/config_mac.mm

 /*
  * Copyright 2009, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 27 matching lines @@
 
 #include <IOKit/IOKitLib.h>
 
 #include <iostream>
 #include <fstream>
 
 #include "plugin/cross/config.h"
 #include "plugin/cross/plugin_metrics.h"
 #include "plugin_mac.h"
 
+namespace o3d {
 
 // Trivial little functions to check for the OS version boundaries we care about
 // and keep the result cached so they are cheap to call repeatedly.
 
 
 // Returns whether OS is 10.4 (Tiger) or higher.
 static bool IsMacOSTenFourOrHigher() {
   static bool isCached = false, result = false;
   if (!isCached) {
     SInt32 major = 0, minor = 0;
@@ skipping 263 matching lines @@
 
   int browser_major = 0, browser_minor = 0, browser_bugfix = 0;
   if (GetBrowserVersionInfo(&browser_major, &browser_minor, &browser_bugfix)) {
     o3d::metric_browser_major_version = browser_major;
     o3d::metric_browser_minor_version = browser_minor;
     o3d::metric_browser_bugfix_version = browser_bugfix;
   }
 
   return true;
 }
+
+}  // namespace o3d