[Mac] Maximise timer slack for background tabs

content/child/child_thread.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_CHILD_CHILD_THREAD_H_
 #define CONTENT_CHILD_CHILD_THREAD_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 177 matching lines @@
     IPC::Sender* const sender_;
   };
 
   void Init();
 
   // IPC message handlers.
   void OnShutdown();
   void OnSetProfilerStatus(tracked_objects::ThreadData::Status status);
   void OnGetChildProfilerData(int sequence_number);
   void OnDumpHandles();
-#if defined(OS_WIN)
   void OnProcessBackgrounded(bool background);
-#endif
 #ifdef IPC_MESSAGE_LOG_ENABLED
   void OnSetIPCLoggingEnabled(bool enable);
 #endif
 #if defined(USE_TCMALLOC)
   void OnGetTcmallocStats();
 #endif
 
   void EnsureConnected();
 
   scoped_ptr<MojoApplication> mojo_application_;
@@ skipping 48 matching lines @@
   scoped_ptr<base::PowerMonitor> power_monitor_;
 
   bool in_browser_process_;
 
   DISALLOW_COPY_AND_ASSIGN(ChildThread);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_CHILD_THREAD_H_