MD5Update function uses StringPiece instead of raw buffer.

chrome/common/metrics_helpers.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/common/metrics_helpers.h"
 
 #if defined(USE_SYSTEM_LIBBZ2)
 #include <bzlib.h>
 #else
 #include "third_party/bzip2/bzlib.h"
@@ skipping 159 matching lines @@
   return std::string(reinterpret_cast<char*>(xml_wrapper_->buffer()->content));
 }
 
 int MetricsLogBase::GetElapsedSeconds() {
   return static_cast<int>((Time::Now() - start_time_).InSeconds());
 }
 
 std::string MetricsLogBase::CreateHash(const std::string& value) {
   base::MD5Context ctx;
   base::MD5Init(&ctx);
-  base::MD5Update(&ctx, value.data(), value.length());
+  base::MD5Update(&ctx, value);
 
   base::MD5Digest digest;
   base::MD5Final(&digest, &ctx);
 
   uint64 reverse_uint64;
   // UMA only uses first 8 chars of hash. We use the above uint64 instead
   // of a unsigned char[8] so that we don't run into strict aliasing issues
   // in the LOG statement below when trying to interpret reverse as a uint64.
   unsigned char* reverse = reinterpret_cast<unsigned char *>(&reverse_uint64);
   DCHECK(arraysize(digest.a) >= sizeof(reverse_uint64));
@@ skipping 394 matching lines @@
     snapshot.Subtract(*already_logged);
   }
 
   // Snapshot now contains only a delta to what we've already_logged.
   if (snapshot.redundant_count() > 0) {
     TransmitHistogramDelta(histogram, snapshot);
     // Add new data into our running total.
     already_logged->Add(snapshot);
   }
 }