Fix Mac gen_snapshot by calling TimerUtils::InitOnce

runtime/bin/gen_snapshot.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include <cstdarg>
 
 #include "include/dart_api.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/eventhandler.h"
 #include "bin/file.h"
 #include "bin/log.h"
 #include "bin/thread.h"
+#include "bin/utils.h"
 #include "bin/vmservice_impl.h"
 
 #include "platform/globals.h"
 
 
 namespace dart {
 namespace bin {
 
 #define CHECK_RESULT(result)                                                   \
   if (Dart_IsError(result)) {                                                  \
@@ skipping 978 matching lines @@
                      argv,
                      &vm_options,
                      &app_script_name) < 0) {
     PrintUsage();
     return 255;
   }
 
   Thread::InitOnce();
   DartUtils::SetOriginalWorkingDirectory();
   // Start event handler.
+  TimerUtils::InitOnce();
   EventHandler::Start();
 
   vm_options.AddArgument("--load_deferred_eagerly");
   // Workaround until issue 21620 is fixed.
   // (https://github.com/dart-lang/sdk/issues/21620)
   vm_options.AddArgument("--no-concurrent_sweep");
 
   if (IsSnapshottingForPrecompilation()) {
     vm_options.AddArgument("--precompilation");
 #if TARGET_ARCH_ARM
@@ skipping 120 matching lines @@
   EventHandler::Stop();
   return 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   return dart::bin::main(argc, argv);
 }