Check that the PNaCl cache hash is truly derived from the bitcode content.

ppapi/native_client/src/trusted/plugin/pnacl_options.h

 // Copyright (c) 2013 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.
 
 #ifndef NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_PNACL_OPTIONS_H_
 #define NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_PNACL_OPTIONS_H_
 
 #include <vector>
 
 #include "native_client/src/include/nacl_string.h"
 #include "native_client/src/include/portability.h"
 
 namespace plugin {
 
 // Options for PNaCl translation.
 class PnaclOptions {
 
  public:
   PnaclOptions();
   ~PnaclOptions();
 
   // Return true if we know the hash of the bitcode, for caching.
   bool HasCacheKey() { return bitcode_hash_ != ""; }
 
   // Return the cache key (which takes into account the bitcode hash,
   // as well as the commandline options).
   nacl::string GetCacheKey();
 
+  // Return just the bitcode hash.
+  nacl::string GetBitcodeHash() { return bitcode_hash_; }
+
   // Return true if the manifest did not specify any special options
   // (just using the default).
   bool HasDefaultOpts() {
     return opt_level_ == -1 && experimental_flags_ == "";
   }
 
   // Return a character array of \x00 delimited commandline options.
   std::vector<char> GetOptCommandline();
 
   bool translate() { return translate_; }
@@ skipping 18 matching lines @@
   // Currently the default copy constructor is good enough, but
   // double-check that it is the case when more fields are added.
   bool translate_;
   int8_t opt_level_;
   nacl::string experimental_flags_;
   nacl::string bitcode_hash_;
 };
 
 }  // namespace plugin;
 #endif  // NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_PNACL_OPTIONS_H_