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

runtime/vm/scopes.cc

 // Copyright (c) 2012, 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/scopes.h"
 
 #include "vm/ast.h"
 #include "vm/bit_vector.h"
 #include "vm/object.h"
 #include "vm/parser.h"
@@ skipping 40 matching lines @@
     if (current_scope == scope) {
       return true;
     }
     current_scope = current_scope->parent();
   }
   return false;
 }
 
 
 bool LocalScope::AddVariable(LocalVariable* variable) {
+  ASSERT(variable != NULL);
   if (LocalLookupVariable(variable->name()) != NULL) {
     return false;
   }
   variables_.Add(variable);
   if (variable->owner() == NULL) {
     // Variables must be added to their owner scope first. Subsequent calls
     // to 'add' treat the variable as an alias.
     variable->set_owner(this);
   }
   return true;
@@ skipping 480 matching lines @@
   } else {
     // Shift negative indexes so that the lowest one is 0 (they are still
     // non-positive).
     return fixed_parameter_count -
         (index() - ParsedFunction::kFirstLocalSlotIndex);
   }
 }
 
 
 }  // namespace dart