Control process backgrounding from within the child process on Windows.

content/child/child_thread.cc

Index: content/child/child_thread.cc
diff --git a/content/child/child_thread.cc b/content/child/child_thread.cc
index 2c06e247ef1ad9a05527af8728ffeb4f08c9e6a5..ab276a67fc7f4126d9d90b46f57736cdd735a362 100644
--- a/content/child/child_thread.cc
+++ b/content/child/child_thread.cc
@@ -441,6 +441,10 @@ bool ChildThread::OnMessageReceived(const IPC::Message& msg) {
     IPC_MESSAGE_HANDLER(ChildProcessMsg_GetChildProfilerData,
                         OnGetChildProfilerData)
     IPC_MESSAGE_HANDLER(ChildProcessMsg_DumpHandles, OnDumpHandles)
+#if defined(OS_WIN)
+    IPC_MESSAGE_HANDLER(ChildProcessMsg_SetProcessBackgrounded,
+                        OnProcessBackgrounded)
+#endif
 #if defined(USE_TCMALLOC)
     IPC_MESSAGE_HANDLER(ChildProcessMsg_GetTcmallocStats, OnGetTcmallocStats)
 #endif
@@ -549,4 +553,10 @@ void ChildThread::EnsureConnected() {
   base::KillProcess(base::GetCurrentProcessHandle(), 0, false);
 }
 
+#if defined(OS_WIN)
+void ChildThread::OnProcessBackgrounded(bool background) {
+  base::Process::Current().SetProcessBackgrounded(background);
+}
+#endif
+
 }  // namespace content