EDK: Remove (direct) dependencies of //mojo/edk/system on //base/test.

mojo/edk/system/test/perf_log.cc

 // 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.
 
-#include "mojo/edk/system/connection_manager.h"
+#include "mojo/edk/system/test/perf_log.h"
+
+#include "base/test/perf_log.h"
 
 namespace mojo {
 namespace system {
+namespace test {
 
-ConnectionIdentifier ConnectionManager::GenerateConnectionIdentifier() {
-  return UniqueIdentifier::Generate(platform_support_);
+void LogPerfResult(const char* test_name, double value, const char* units) {
+  base::LogPerfResult(test_name, value, units);
 }
 
+}  // namespace test
 }  // namespace system
 }  // namespace mojo