C++ Readability review for holte

components/rappor/rappor_metric.cc

 // Copyright 2014 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.
 
+// Change for readability
+
 #include "components/rappor/rappor_metric.h"
 
 #include "base/logging.h"
 
 namespace rappor {
 
 RapporMetric::RapporMetric(const std::string& metric_name,
                            const RapporParameters& parameters,
                            int32_t cohort)
     : metric_name_(metric_name),
       parameters_(parameters),
       bloom_filter_(parameters.bloom_filter_size_bytes,
                     parameters.bloom_filter_hash_function_count,
                     cohort * parameters.bloom_filter_hash_function_count) {
   DCHECK_GE(cohort, 0);
 }
 
 RapporMetric::~RapporMetric() {}
 
 void RapporMetric::AddSample(const std::string& str) {
   bloom_filter_.AddString(str);
 }
 
 ByteVector RapporMetric::GetReport(const std::string& secret) const {
   // Generate a deterministically random mask of fake data using the
   // client's secret key + real data as a seed.  The inclusion of the secret
   // in the seed avoids correlations between real and fake data.
   // The seed isn't a human-readable string.
-  std::string personalization_string = metric_name_ +
+  const std::string personalization_string = metric_name_ +
       std::string(bytes().begin(), bytes().end());
   HmacByteVectorGenerator hmac_generator(bytes().size(), secret,
                                          personalization_string);
   const ByteVector fake_mask =
       hmac_generator.GetWeightedRandomByteVector(parameters().fake_prob);
   ByteVector fake_bits =
       hmac_generator.GetWeightedRandomByteVector(parameters().fake_one_prob);
 
   // Redact most of the real data by replacing it with the fake data, hiding
   // and limiting the amount of information an individual client reports on.
   const ByteVector* fake_and_redacted_bits =
       ByteVectorMerge(fake_mask, bytes(), &fake_bits);
 
   // Generate biased coin flips for each bit.
   ByteVectorGenerator coin_generator(bytes().size());
   const ByteVector zero_coins =
       coin_generator.GetWeightedRandomByteVector(parameters().zero_coin_prob);
   ByteVector one_coins =
       coin_generator.GetWeightedRandomByteVector(parameters().one_coin_prob);
 
   // Create a randomized response report on the fake and redacted data, sending
   // the outcome of flipping a zero coin for the zero bits in that data, and of
   // flipping a one coin for the one bits in that data, as the final report.
   return *ByteVectorMerge(*fake_and_redacted_bits, zero_coins, &one_coins);
 }
 
 }  // namespace rappor