EDK: Move ref counting classes to mojo/edk/util.

mojo/edk/system/message_pipe_perftest.cc

Index: mojo/edk/system/message_pipe_perftest.cc
diff --git a/mojo/edk/system/message_pipe_perftest.cc b/mojo/edk/system/message_pipe_perftest.cc
index ad892ddc6f19a83366f02b745a1177f222a534a9..77169385386008981705bd00d5a06decf4e1f70f 100644
--- a/mojo/edk/system/message_pipe_perftest.cc
+++ b/mojo/edk/system/message_pipe_perftest.cc
@@ -15,13 +15,15 @@
 #include "mojo/edk/system/message_pipe.h"
 #include "mojo/edk/system/message_pipe_test_utils.h"
 #include "mojo/edk/system/proxy_message_pipe_endpoint.h"
-#include "mojo/edk/system/ref_ptr.h"
 #include "mojo/edk/system/test/perf_log.h"
 #include "mojo/edk/system/test/stopwatch.h"
 #include "mojo/edk/test/test_utils.h"
+#include "mojo/edk/util/ref_ptr.h"
 #include "mojo/public/cpp/system/macros.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+using mojo::util::RefPtr;
+
 namespace mojo {
 namespace system {
 namespace {