Store pointer instead of reference to LocalVariable in ast and flow graph.

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
===================================================================
--- runtime/vm/intermediate_language.cc	(revision 10207)
+++ runtime/vm/intermediate_language.cc	(working copy)
@@ -457,8 +457,8 @@
 
 void StoreLocalComp::RecordAssignedVars(BitVector* assigned_vars,
                                         intptr_t fixed_parameter_count) {
-  if (!local().is_captured()) {
-    assigned_vars->Add(local().BitIndexIn(fixed_parameter_count));
+  if (!local()->is_captured()) {
+    assigned_vars->Add(local()->BitIndexIn(fixed_parameter_count));
   }
 }
 
@@ -754,7 +754,7 @@
 RawAbstractType* LoadLocalComp::StaticType() const {
   // TODO(regis): Verify that the type of the receiver is properly set.
   if (FLAG_enable_type_checks) {
-    return local().type().raw();
+    return local()->type().raw();
   }
   return Type::DynamicType();
 }