Remove dead isLocalPort from the VM mirrors implementation.

runtime/lib/mirrors.cc

Index: runtime/lib/mirrors.cc
diff --git a/runtime/lib/mirrors.cc b/runtime/lib/mirrors.cc
index 3f7e05828a67d710b649e4d35ea279ff8cd00ca1..3d228cdf4bb0eb05627855a8ff2437639644284d 100644
--- a/runtime/lib/mirrors.cc
+++ b/runtime/lib/mirrors.cc
@@ -97,22 +97,6 @@ static void ThrowNoSuchMethod(const Instance& receiver,
 }
 
 
-DEFINE_NATIVE_ENTRY(Mirrors_isLocalPort, 1) {
-  GET_NON_NULL_NATIVE_ARGUMENT(Instance, port, arguments->NativeArgAt(0));
-
-  // Get the port id from the SendPort instance.
-  const Object& id_obj = Object::Handle(DartLibraryCalls::PortGetId(port));
-  if (id_obj.IsError()) {
-    Exceptions::PropagateError(Error::Cast(id_obj));
-    UNREACHABLE();
-  }
-  ASSERT(id_obj.IsSmi() || id_obj.IsMint());
-  Integer& id = Integer::Handle();
-  id ^= id_obj.raw();
-  Dart_Port port_id = static_cast<Dart_Port>(id.AsInt64Value());
-  return Bool::Get(PortMap::IsLocalPort(port_id)).raw();
-}
-
 static void EnsureConstructorsAreCompiled(const Function& func) {
   // Only generative constructors can have initializing formals.
   if (!func.IsConstructor()) return;