[Mac] Maximise timer slack for background tabs

content/browser/renderer_host/render_process_host_impl.cc

 // 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 1995 matching lines @@
 
 #if defined(OS_WIN)
   // The cbstext.dll loads as a global GetMessage hook in the browser process
   // and intercepts/unintercepts the kernel32 API SetPriorityClass in a
   // background thread. If the UI thread invokes this API just when it is
   // intercepted the stack is messed up on return from the interceptor
   // which causes random crashes in the browser process. Our hack for now
   // is to not invoke the SetPriorityClass API if the dll is loaded.
   if (GetModuleHandle(L"cbstext.dll"))
     return;
+#endif  // OS_WIN
+
+  // Notify the child process of background state.
+  Send(new ChildProcessMsg_SetProcessBackgrounded(backgrounded));
+
+#if !defined(OS_WIN)
+  // Backgrounding may require elevated privileges not available to renderer
+  // processes, so control backgrounding from the process host.
 
   // Windows Vista+ has a fancy process backgrounding mode that can only be set
-  // from within the process.  So notify the child process of background state.
-  Send(new ChildProcessMsg_SetProcessBackgrounded(backgrounded));
-#else
-
-  // Backgrounding may require elevated privileges not available to renderer
-  // processes, so control backgrounding from the process host.
+  // from within the process.
   child_process_launcher_->SetProcessBackgrounded(backgrounded);
-#endif  // OS_WIN
+#endif  // !OS_WIN
 }
 
 void RenderProcessHostImpl::OnProcessLaunched() {
   // No point doing anything, since this object will be destructed soon.  We
   // especially don't want to send the RENDERER_PROCESS_CREATED notification,
   // since some clients might expect a RENDERER_PROCESS_TERMINATED afterwards to
   // properly cleanup.
   if (deleting_soon_)
     return;
 
@@ skipping 213 matching lines @@
 void RenderProcessHostImpl::GpuMemoryBufferAllocated(
     IPC::Message* reply,
     const gfx::GpuMemoryBufferHandle& handle) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   ChildProcessHostMsg_SyncAllocateGpuMemoryBuffer::WriteReplyParams(reply,
                                                                     handle);
   Send(reply);
 }
 
 }  // namespace content