Always initialize the EventHandler in the standalone.

runtime/bin/eventhandler_macos.cc

Index: runtime/bin/eventhandler_macos.cc
diff --git a/runtime/bin/eventhandler_macos.cc b/runtime/bin/eventhandler_macos.cc
index 419c93e4518cb899a4ce7b1c62a9b17b2f29112d..20c6b61383fc5e586ad348c72bfe093885a3c6de 100644
--- a/runtime/bin/eventhandler_macos.cc
+++ b/runtime/bin/eventhandler_macos.cc
@@ -184,6 +184,9 @@ void EventHandlerImplementation::WakeupHandler(intptr_t id,
   msg.id = id;
   msg.dart_port = dart_port;
   msg.data = data;
+  // WriteToBlocking will write up to 512 bytes atomically, and since our msg
+  // is smaller than 512, we don't need a thread lock.
+  // See: http://linux.die.net/man/7/pipe, section 'Pipe_buf'.

[Ivan Posva, 2013/08/23 00:14:16]

It is a bit questionable quoting a Linux man page for a Mac OS X implementation.

[Anders Johnsen, 2013/08/23 05:15:27]

You are right. I was not able to find it in a mac os x man page, but I did find
it in some books when searching. I'm adding the assert and removing the link.

   intptr_t result =
       FDUtils::WriteToBlocking(interrupt_fds_[1], &msg, kInterruptMessageSize);
   if (result != kInterruptMessageSize) {