Change the thread interface in runtime/platform and use it starting all threads

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 d3fe8c80af2e00d821ba18bb060de52d89d4d70a..bc498af630209fc233d3eab74b2746e799f58976 100644
--- a/runtime/bin/eventhandler_macos.cc
+++ b/runtime/bin/eventhandler_macos.cc
@@ -2,6 +2,8 @@
 // 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.
 
+#include "bin/eventhandler.h"
+
 #include <errno.h>
 #include <poll.h>
 #include <pthread.h>
@@ -10,7 +12,6 @@
 #include <sys/time.h>
 #include <unistd.h>
 
-#include "bin/eventhandler.h"
 #include "bin/fdutils.h"
 
 
@@ -339,7 +340,7 @@ void EventHandlerImplementation::HandleTimeout() {
 }
 
 
-void* EventHandlerImplementation::Poll(void* args) {
+void EventHandlerImplementation::Poll(uword args) {
   intptr_t pollfds_size;
   struct pollfd* pollfds;
   EventHandlerImplementation* handler =
@@ -359,17 +360,13 @@ void* EventHandlerImplementation::Poll(void* args) {
     }
     free(pollfds);
   }
-  return NULL;
 }
 
 
 void EventHandlerImplementation::StartEventHandler() {
-  pthread_t handler_thread;
-  int result = pthread_create(&handler_thread,
-                              NULL,
-                              &EventHandlerImplementation::Poll,
-                              this);
-  if (result != 0) {
+  dart::ThreadHandle handle = dart::Thread::Start(
+      &EventHandlerImplementation::Poll, reinterpret_cast<uword>(this));
+  if (handle == dart::Thread::kInvalidThreadHandle) {
     FATAL("Create start event handler thread");
   }
 }