Remove calls to deprecated MessageLoop methods in net.

net/http/http_response_body_drainer_unittest.cc

Index: net/http/http_response_body_drainer_unittest.cc
diff --git a/net/http/http_response_body_drainer_unittest.cc b/net/http/http_response_body_drainer_unittest.cc
index 920e14442bcc36c2db955290356b08e81df1b5a2..078f9a1c4fc33dd5c34aaa7956b23bfd54c63ef9 100644
--- a/net/http/http_response_body_drainer_unittest.cc
+++ b/net/http/http_response_body_drainer_unittest.cc
@@ -14,6 +14,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "net/base/io_buffer.h"
@@ -50,7 +51,7 @@ class CloseResultWaiter {
     CHECK(!waiting_for_result_);
     while (!have_result_) {
       waiting_for_result_ = true;
-      base::MessageLoop::current()->Run();
+      base::RunLoop().Run();
       waiting_for_result_ = false;
     }
     return result_;