Make ProcessWatcher use kqueues on Mac.

chrome/browser/child_process_launcher.cc

 // Copyright (c) 2009 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.
 
 #include "chrome/browser/child_process_launcher.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/scoped_ptr.h"
 #include "base/thread.h"
@@ skipping 210 matching lines @@
     // means that UMA won't treat this as a crash.
     process.Terminate(ResultCodes::NORMAL_EXIT);
     // On POSIX, we must additionally reap the child.
 #if defined(OS_POSIX)
 #if defined(OS_LINUX)
     if (zygote) {
       // If the renderer was created via a zygote, we have to proxy the reaping
       // through the zygote process.
       Singleton<ZygoteHost>()->EnsureProcessTerminated(handle);
     } else
-#endif  // defined(OS_LINUX)
+#endif  // OS_LINUX
     {
       ProcessWatcher::EnsureProcessTerminated(handle);
     }
-#endif
+#endif  // OS_POSIX
     process.Close();
   }
 
   Client* client_;
   ChromeThread::ID client_thread_id_;
   base::Process process_;
   bool starting_;
 
 #if defined(OS_LINUX)
   bool zygote_;
@@ skipping 57 matching lines @@
   if (child_exited)
     context_->process_.Close();
 
   return did_crash;
 }
 
 void ChildProcessLauncher::SetProcessBackgrounded(bool background) {
   DCHECK(!context_->starting_);
   context_->process_.SetProcessBackgrounded(background);
 }