VM: Add result cid information for recognized methods.

runtime/vm/flow_graph_type_propagator.cc

Index: runtime/vm/flow_graph_type_propagator.cc
diff --git a/runtime/vm/flow_graph_type_propagator.cc b/runtime/vm/flow_graph_type_propagator.cc
index d0ffe7707e57d67f1eb6093a54c55ddaaffc28af..2ee8ed12520d69003970ed9446da48be58a76ca4 100644
--- a/runtime/vm/flow_graph_type_propagator.cc
+++ b/runtime/vm/flow_graph_type_propagator.cc
@@ -888,6 +888,15 @@ CompileType AllocateUninitializedContextInstr::ComputeType() const {
 }
 
 
+CompileType PolymorphicInstanceCallInstr::ComputeType() const {
+  if (!HasSingleRecognizedTarget()) return CompileType::Dynamic();
+  const Function& target = Function::Handle(ic_data().GetTargetAt(0));
+  return (target.recognized_kind() != MethodRecognizer::kUnknown)
+      ? CompileType::FromCid(MethodRecognizer::ResultCid(target))
+      : CompileType::Dynamic();
+}
+
+
 CompileType StaticCallInstr::ComputeType() const {
   if (result_cid_ != kDynamicCid) {
     return CompileType::FromCid(result_cid_);