base: Allow renderer thread priorities to be changed.

content/child/child_thread_impl.cc

Index: content/child/child_thread_impl.cc
diff --git a/content/child/child_thread_impl.cc b/content/child/child_thread_impl.cc
index 29454b64e1ab12feba98ce80e1d88bb66093b504..380d4410d4a955f55b068527463e7b4b93e5d8b3 100644
--- a/content/child/child_thread_impl.cc
+++ b/content/child/child_thread_impl.cc
@@ -731,6 +731,13 @@ std::unique_ptr<base::SharedMemory> ChildThreadImpl::AllocateSharedMemory(
   return shared_buf;
 }
 
+#if defined(OS_LINUX)
+void ChildThreadImpl::SetThreadPriority(base::PlatformThreadId id,
+                                        base::ThreadPriority priority) {
+  Send(new ChildProcessHostMsg_SetThreadPriority(id, priority));
+}
+#endif
+
 bool ChildThreadImpl::OnMessageReceived(const IPC::Message& msg) {
   // Resource responses are sent to the resource dispatcher.
   if (resource_dispatcher_->OnMessageReceived(msg))