Add DISALLOW_COPY_AND_ASSIGN to subclasses of ValueObject and make ValueObject copyable.

runtime/vm/flow_graph.h

 // 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.
 
 #ifndef VM_FLOW_GRAPH_H_
 #define VM_FLOW_GRAPH_H_
 
 #include "vm/growable_array.h"
 #include "vm/intermediate_language.h"
 #include "vm/parser.h"
@@ skipping 18 matching lines @@
     current_++;
   }
 
   bool Done() const { return current_ >= block_order_.length(); }
 
   BlockEntryInstr* Current() const { return block_order_[current_]; }
 
  private:
   const GrowableArray<BlockEntryInstr*>& block_order_;
   intptr_t current_;
+
+  // Disallow operator=. Use public copy constructor for copying instead.
+  BlockIterator& operator=(const BlockIterator& other);
 };
 
 
 // Class to incapsulate the construction and manipulation of the flow graph.
 class FlowGraph : public ZoneAllocated {
  public:
   FlowGraph(const FlowGraphBuilder& builder,
             GraphEntryInstr* graph_entry,
             intptr_t max_block_id);
 
@@ skipping 140 matching lines @@
   GrowableArray<BlockEntryInstr*> preorder_;
   GrowableArray<BlockEntryInstr*> postorder_;
   GrowableArray<BlockEntryInstr*> reverse_postorder_;
   bool invalid_dominator_tree_;
   ConstantInstr* constant_null_;
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_H_