Avoid needless int64_t to intptr_t conversion in eventhandler.

runtime/bin/eventhandler.cc

Index: runtime/bin/eventhandler.cc
diff --git a/runtime/bin/eventhandler.cc b/runtime/bin/eventhandler.cc
index 5689676d4f0dfc71bdc457f5925f9a003d1bb704..c1e88e7e1e86adc2a775b20b77c2fa844f83edd8 100644
--- a/runtime/bin/eventhandler.cc
+++ b/runtime/bin/eventhandler.cc
@@ -72,7 +72,7 @@ void FUNCTION_NAME(EventHandler_SendData)(Dart_NativeArguments args) {
   handle = Dart_GetNativeArgument(args, 2);
   Dart_Port dart_port =
       DartUtils::GetIntegerField(handle, DartUtils::kIdFieldName);
-  intptr_t data = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 3));
+  int64_t data = DartUtils::GetIntegerValue(Dart_GetNativeArgument(args, 3));
   event_handler->SendData(id, dart_port, data);
   Dart_ExitScope();
 }