Fix another unused-private-field clang error.

dart/runtime/vm/intermediate_language.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_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 1055 matching lines @@
   // preorder number.
   BitVector* loop_info_;
 
   DISALLOW_COPY_AND_ASSIGN(BlockEntryInstr);
 };
 
 
 class ForwardInstructionIterator : public ValueObject {
  public:
   explicit ForwardInstructionIterator(BlockEntryInstr* block_entry)
-      : block_entry_(block_entry), current_(block_entry) {
+      : current_(block_entry) {
     Advance();
   }
 
   void Advance() {
     ASSERT(!Done());
     current_ = current_->next();
   }
 
   bool Done() const { return current_ == NULL; }
 
   // Removes 'current_' from graph and sets 'current_' to previous instruction.
   void RemoveCurrentFromGraph();
 
   Instruction* Current() const { return current_; }
 
  private:
-  BlockEntryInstr* block_entry_;
   Instruction* current_;
 };
 
 
 class BackwardInstructionIterator : public ValueObject {
  public:
   explicit BackwardInstructionIterator(BlockEntryInstr* block_entry)
       : block_entry_(block_entry), current_(block_entry->last_instruction()) {
     ASSERT(block_entry_->previous() == NULL);
   }
@@ skipping 3836 matching lines @@
   ForwardInstructionIterator* current_iterator_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_