Fix some chromium-style warnings in webrtc/system_wrappers/

BUG=163
R=henrike@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1906004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4464 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/system_wrappers/source/thread.cc b/webrtc/system_wrappers/source/thread.cc
index 6f023f8..b5ee7a5 100644
--- a/webrtc/system_wrappers/source/thread.cc
+++ b/webrtc/system_wrappers/source/thread.cc
@@ -28,4 +28,9 @@
 #endif
 }
 
+bool ThreadWrapper::SetAffinity(const int* processor_numbers,
+                                const unsigned int amount_of_processors) {
+  return false;
+}
+
 }  // namespace webrtc