Make mojo::RunLoop just use pthreads.

mojo/public/cpp/utility/run_loop.h

Index: mojo/public/cpp/utility/run_loop.h
diff --git a/mojo/public/cpp/utility/run_loop.h b/mojo/public/cpp/utility/run_loop.h
index 42e59500224abbae0ee4ffbaa0badee2da9ff938..71aa74e6141124b1dfa199d2fe5f83a96a7ceda0 100644
--- a/mojo/public/cpp/utility/run_loop.h
+++ b/mojo/public/cpp/utility/run_loop.h
@@ -25,13 +25,6 @@ class RunLoop {
   RunLoop();
   ~RunLoop();
 
-  // Sets up state needed for RunLoop. This must be invoked before creating a
-  // RunLoop.
-  static void SetUp();
-
-  // Cleans state created by Setup().
-  static void TearDown();
-
   // Returns the RunLoop for the current thread. Returns null if not yet
   // created.
   static RunLoop* current();