Revert "Optimize the message queue for many active ports with few messages."

runtime/vm/isolate.cc

Index: runtime/vm/isolate.cc
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index 061cf7cbc4a35844b1754e623a7709eb3e914dfc..fee9cbb8a331bacdbc54ac56479a4ceea34b69d5 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -89,21 +89,6 @@ bool IsolateMessageHandler::HandleMessage(Message* message) {
   StackZone zone(isolate_);
   HandleScope handle_scope(isolate_);
 
-  // If the message is in band we lookup the receive port to dispatch to.  If
-  // the receive port is closed, we drop the message without deserializing it.
-  Object& receive_port = Object::Handle();
-  if (!message->IsOOB()) {
-    receive_port = DartLibraryCalls::LookupReceivePort(message->dest_port());
-    if (receive_port.IsError()) {
-      return ProcessUnhandledException(Instance::Handle(),
-                                       Error::Cast(receive_port));
-    }
-    if (receive_port.IsNull()) {
-      delete message;
-      return true;
-    }
-  }
-
   // Parse the message.
   SnapshotReader reader(message->data(), message->len(),
                         Snapshot::kMessage, Isolate::Current());
@@ -131,7 +116,7 @@ bool IsolateMessageHandler::HandleMessage(Message* message) {
   } else {
     const Object& result = Object::Handle(
         DartLibraryCalls::HandleMessage(
-            receive_port, message->reply_port(), msg));
+            message->dest_port(), message->reply_port(), msg));
     if (result.IsError()) {
       success = ProcessUnhandledException(msg, Error::Cast(result));
     } else {