Reorganize histograms for persistence.

net/dns/dns_session.cc

 // Copyright (c) 2012 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 "net/dns/dns_session.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 18 matching lines @@
 
 // Number of buckets in the histogram of observed RTTs.
 const size_t kRTTBucketCount = 100;
 // Target percentile in the RTT histogram used for retransmission timeout.
 const unsigned kRTOPercentile = 99;
 }  // namespace
 
 // Runtime statistics of DNS server.
 struct DnsSession::ServerStats {
   ServerStats(base::TimeDelta rtt_estimate_param, RttBuckets* buckets)
-    : last_failure_count(0), rtt_estimate(rtt_estimate_param) {
-    rtt_histogram.reset(new base::SampleVector(buckets));
+      : last_failure_count(0), rtt_estimate(rtt_estimate_param) {
+    rtt_histogram.reset(new base::SampleVector(0, buckets));
     // Seed histogram with 2 samples at |rtt_estimate| timeout.
     rtt_histogram->Accumulate(
         static_cast<base::HistogramBase::Sample>(rtt_estimate.InMilliseconds()),
         2);
   }
 
   // Count of consecutive failures after last success.
   int last_failure_count;
 
   // Last time when server returned failure or timeout.
@@ skipping 242 matching lines @@
   timeout = std::max(timeout, base::TimeDelta::FromMilliseconds(kMinTimeoutMs));
 
   // The timeout still doubles every full round.
   unsigned num_backoffs = attempt / config_.nameservers.size();
 
   return std::min(timeout * (1 << num_backoffs),
                   base::TimeDelta::FromMilliseconds(kMaxTimeoutMs));
 }
 
 }  // namespace net