Avoid needless int64_t to intptr_t conversion in eventhandler.

runtime/bin/eventhandler_linux.cc

 // Copyright (c) 2012, 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.
 
 #include "bin/eventhandler.h"
 
 #include <errno.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <string.h>
@@ skipping 394 matching lines @@
 }
 
 
 void EventHandlerImplementation::Shutdown() {
   SendData(kShutdownId, 0, 0);
 }
 
 
 void EventHandlerImplementation::SendData(intptr_t id,
                                           Dart_Port dart_port,
-                                          intptr_t data) {
+                                          int64_t data) {
   WakeupHandler(id, dart_port, data);
 }
 
 
 void* EventHandlerImplementation::GetHashmapKeyFromFd(intptr_t fd) {
   // The hashmap does not support keys with value 0.
   return reinterpret_cast<void*>(fd + 1);
 }
 
 
 uint32_t EventHandlerImplementation::GetHashmapHashFromFd(intptr_t fd) {
   // The hashmap does not support keys with value 0.
   return dart::Utils::WordHash(fd + 1);
 }