Adds a special case for sending an int over a port with the native API.

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index f8133efa01441bf6c2a1b3e9a705498c4d8cb102..73e7e16c5cc1676a864f2bbc0655b62b19447193 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -468,24 +468,28 @@ MessageHandler::MessageStatus IsolateMessageHandler::HandleMessage(
   }
 
   // Parse the message.
-  MessageSnapshotReader reader(message->data(), message->len(), thread);
-  const Object& msg_obj = Object::Handle(zone, reader.ReadObject());
-  if (msg_obj.IsError()) {
-    // An error occurred while reading the message.
-    delete message;
-    return ProcessUnhandledException(Error::Cast(msg_obj));
-  }
-  if (!msg_obj.IsNull() && !msg_obj.IsInstance()) {
-    // TODO(turnidge): We need to decide what an isolate does with
-    // malformed messages.  If they (eventually) come from a remote
-    // machine, then it might make sense to drop the message entirely.
-    // In the case that the message originated locally, which is
-    // always true for now, then this should never occur.
-    UNREACHABLE();
-  }
-
   Instance& msg = Instance::Handle(zone);
-  msg ^= msg_obj.raw();  // Can't use Instance::Cast because may be null.
+  if (message->type() == Message::kDataType) {
+    MessageSnapshotReader reader(message->data(), message->len(), thread);
+    const Object& msg_obj = Object::Handle(zone, reader.ReadObject());
+    if (msg_obj.IsError()) {
+      // An error occurred while reading the message.
+      delete message;
+      return ProcessUnhandledException(Error::Cast(msg_obj));
+    }
+    if (!msg_obj.IsNull() && !msg_obj.IsInstance()) {
+      // TODO(turnidge): We need to decide what an isolate does with
+      // malformed messages.  If they (eventually) come from a remote
+      // machine, then it might make sense to drop the message entirely.
+      // In the case that the message originated locally, which is
+      // always true for now, then this should never occur.
+      UNREACHABLE();
+    }
+    msg ^= msg_obj.raw();  // Can't use Instance::Cast because may be null.
+  } else {
+    ASSERT(message->type() == Message::kIntegerType);
+    msg ^= Smi::New(message->integer());
+  }
 
   MessageStatus status = kOK;
   if (message->IsOOB()) {