- Address warnings about 64-bit to 32-bit conversions.

runtime/lib/isolate.cc

Index: runtime/lib/isolate.cc
===================================================================
--- runtime/lib/isolate.cc	(revision 31816)
+++ runtime/lib/isolate.cc	(working copy)
@@ -43,7 +43,7 @@
 
 
 // TODO(turnidge): Move to DartLibraryCalls.
-static RawObject* ReceivePortCreate(intptr_t port_id) {
+static RawObject* ReceivePortCreate(Dart_Port port_id) {
   Isolate* isolate = Isolate::Current();
   Function& func =
       Function::Handle(isolate,
@@ -78,7 +78,7 @@
 DEFINE_NATIVE_ENTRY(RawReceivePortImpl_factory, 1) {
   ASSERT(AbstractTypeArguments::CheckedHandle(
       arguments->NativeArgAt(0)).IsNull());
-  intptr_t port_id =
+  Dart_Port port_id =
       PortMap::CreatePort(arguments->isolate()->message_handler());
   const Object& port = Object::Handle(ReceivePortCreate(port_id));
   if (port.IsError()) {