Background compiler should validate CHA decisions before committing the code.

runtime/vm/jit_optimizer.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/jit_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/branch_optimizer.h"
 #include "vm/cha.h"
 #include "vm/compiler.h"
@@ skipping 2373 matching lines @@
 
   // Private classes cannot be subclassed by later loaded libs.
   if (!type_class.IsPrivate()) {
     if (FLAG_use_cha_deopt || isolate()->all_classes_finalized()) {
       if (FLAG_trace_cha) {
         THR_Print("  **(CHA) Typecheck as class equality since no "
             "subclasses: %s\n",
             type_class.ToCString());
       }
       if (FLAG_use_cha_deopt) {
-        thread()->cha()->AddToLeafClasses(type_class);
+        thread()->cha()->AddToGuardedClasses(type_class, /*subclass_count=*/0);
       }
     } else {
       return false;
     }
   }
   const intptr_t num_type_args = type_class.NumTypeArguments();
   if (num_type_args > 0) {
     // Only raw types can be directly compared, thus disregarding type
     // arguments.
     const intptr_t num_type_params = type_class.NumTypeParameters();
@@ skipping 676 matching lines @@
 
   // Discard the environment from the original instruction because the store
   // can't deoptimize.
   instr->RemoveEnvironment();
   ReplaceCall(instr, store);
   return true;
 }
 
 
 }  // namespace dart