Fix some issues found looking at the code....

base/hmac.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Utility class for calculating the HMAC for a given message. We currently
 // only support SHA1 for the hash algorithm, but this can be extended easily.
 
 #ifndef BASE_HMAC_H_
 #define BASE_HMAC_H_
 
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/scoped_ptr.h"
 
 namespace base {
 
 // Simplify the interface and reduce includes by abstracting out the internals.
 struct HMACPlatformData;
 
 class HMAC {
  public:
   // The set of supported hash functions. Extend as required.
   enum HashAlgorithm {
     SHA1
   };
 
   HMAC(HashAlgorithm hash_alg, const unsigned char* key, int key_length);
   ~HMAC();
 
   // Calculates the HMAC for the message in |data| using the algorithm and key
   // supplied to the constructor.  The HMAC is returned in |digest|, which
   // has |digest_length| bytes of storage available.
   bool Sign(const std::string& data, unsigned char* digest, int digest_length);
 
  private:
   HashAlgorithm hash_alg_;
-  HMACPlatformData* plat_;
+  scoped_ptr<HMACPlatformData> plat_;
 
   DISALLOW_COPY_AND_ASSIGN(HMAC);
 };
 
 }  // namespace base
 
 #endif  // BASE_HMAC_H_