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

mojo/edk/util/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("../mojo_edk.gni")
 
 mojo_edk_source_set("util") {
   sources = [
     "make_unique.h",
+    "ref_counted.h",
+    "ref_counted_internal.h",
+    "ref_ptr.h",
+    "ref_ptr_internal.h",
     "scoped_file.h",
   ]
 
   mojo_edk_configs = [ "mojo/edk/system:system_config" ]
+
+  mojo_sdk_public_deps = [ "mojo/public/cpp/system" ]
 }
+
+mojo_edk_source_set("unittests") {
+  testonly = true
+  mojo_edk_visibility = [ "mojo/edk/system:mojo_system_unittests" ]
+
+  sources = [
+    "ref_counted_unittest.cc",
+  ]
+
+  mojo_sdk_deps = [ "mojo/public/cpp/system" ]
+
+  deps = [
+    ":util",
+    "//testing/gtest",
+  ]
+}
+
+mojo_edk_source_set("perftests") {
+  testonly = true
+  mojo_edk_visibility = [ "mojo/edk/system:mojo_system_perftests" ]
+
+  sources = [
+    "ref_counted_perftest.cc",
+  ]
+
+  deps = [
+    ":util",
+    "//testing/gtest",
+  ]
+
+  mojo_edk_deps = [
+    "mojo/edk/system/test",
+    "mojo/edk/system/test:perf",
+  ]
+}