Revert

runtime/vm/flow_graph_optimizer.cc

Index: runtime/vm/flow_graph_optimizer.cc
===================================================================
--- runtime/vm/flow_graph_optimizer.cc	(revision 27672)
+++ runtime/vm/flow_graph_optimizer.cc	(working copy)
@@ -1570,6 +1570,20 @@
 }
 
 
+void FlowGraphOptimizer::AddToGuardedFields(const Field& field) {
+  if ((field.guarded_cid() == kDynamicCid) ||
+      (field.guarded_cid() == kIllegalCid)) {
+    return;
+  }
+  for (intptr_t j = 0; j < guarded_fields_->length(); j++) {
+    if ((*guarded_fields_)[j]->raw() == field.raw()) {
+      return;
+    }
+  }
+  guarded_fields_->Add(&field);
+}
+
+
 void FlowGraphOptimizer::InlineImplicitInstanceGetter(InstanceCallInstr* call) {
   ASSERT(call->HasICData());
   const ICData& ic_data = *call->ic_data();
@@ -1596,7 +1610,7 @@
     if (!field.is_nullable() || (field.guarded_cid() == kNullCid)) {
       load->set_result_cid(field.guarded_cid());
     }
-    flow_graph_->builder().AddToGuardedFields(field);
+    AddToGuardedFields(field);
   }
 
   // Discard the environment from the original instruction because the load