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/interface/thread_wrapper.h b/webrtc/system_wrappers/interface/thread_wrapper.h
index d9e7d8a..7fbf58c 100644
--- a/webrtc/system_wrappers/interface/thread_wrapper.h
+++ b/webrtc/system_wrappers/interface/thread_wrapper.h
@@ -78,9 +78,7 @@
   // should be lower than (number of CPUs - 1). amount_of_processors should be
   // equal to the number of processors listed in processor_numbers.
   virtual bool SetAffinity(const int* processor_numbers,
-                           const unsigned int amount_of_processors) {
-    return false;
-  }
+                           const unsigned int amount_of_processors);
 
   // Stops the spawned thread and waits for it to be reclaimed with a timeout
   // of two seconds. Will return false if the thread was not reclaimed.