Clean up PlatformThread.

webrtc/base/signalthread.cc

Index: webrtc/base/signalthread.cc
diff --git a/webrtc/base/signalthread.cc b/webrtc/base/signalthread.cc
index d03f38641666af9d754ac3744dd525654be6fcf2..75f7b773152d13e67dbe55ee4f7578c8485c8450 100644
--- a/webrtc/base/signalthread.cc
+++ b/webrtc/base/signalthread.cc
@@ -39,13 +39,6 @@ bool SignalThread::SetName(const std::string& name, const void* obj) {
   return worker_.SetName(name, obj);
 }
 
-bool SignalThread::SetPriority(ThreadPriority priority) {
-  EnterExit ee(this);
-  ASSERT(main_->IsCurrent());
-  ASSERT(kInit == state_);
-  return worker_.SetPriority(priority);
-}
-
 void SignalThread::Start() {
   EnterExit ee(this);
   ASSERT(main_->IsCurrent());