Refactoring using TempAssign.

src/utils.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 359 matching lines @@
   T* start_;
   int length_;
 };
 
 
 // A temporary assignment sets a (non-local) variable to a value on
 // construction and resets it the value on destruction.
 template <typename T>
 class TempAssign {
  public:
-  TempAssign(T* var, T value): var_(var), old_value_(*var) {
+  TempAssign(T* var, const T& value): var_(var), old_value_(*var) {
     *var = value;
   }
 
   ~TempAssign() { *var_ = old_value_; }
 
+  const T& old_value() const { return old_value_; };
+
  private:
   T* var_;
   T old_value_;
 };
 
 
 template <typename T, int kSize>
 class EmbeddedVector : public Vector<T> {
  public:
   EmbeddedVector() : Vector<T>(buffer_, kSize) { }
@@ skipping 176 matching lines @@
   ptr[2] = value >> 8;
   ptr[1] = value >> 16;
   ptr[0] = value >> 24;
 #endif
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_UTILS_H_