Fix for issue 25236

runtime/vm/os_thread_macos.cc

Index: runtime/vm/os_thread_macos.cc
diff --git a/runtime/vm/os_thread_macos.cc b/runtime/vm/os_thread_macos.cc
index 2fa58d85456e73334b5501e2b501079ca4070e90..1964f64c84495e34b5bb34cfafa990fffae82897 100644
--- a/runtime/vm/os_thread_macos.cc
+++ b/runtime/vm/os_thread_macos.cc
@@ -88,12 +88,14 @@ static void* ThreadStart(void* data_ptr) {
   delete data;
 
   // Create new OSThread object and set as TLS for new thread.
-  OSThread* thread = new OSThread();
-  OSThread::SetCurrent(thread);
-  thread->set_name(name);
+  OSThread* thread = OSThread::CreateOSThread();
+  if (thread != NULL) {
+    OSThread::SetCurrent(thread);
+    thread->set_name(name);
 
-  // Call the supplied thread start function handing it its parameters.
-  function(parameter);
+    // Call the supplied thread start function handing it its parameters.
+    function(parameter);
+  }
 
   return NULL;
 }