Use factory to create histograms, and refcounts to track lifetimes...

net/disk_cache/stats.cc

 // 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.
 
 #include "net/disk_cache/stats.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "net/disk_cache/backend_impl.h"
@@ skipping 120 matching lines @@
   // It seems impossible to support this histogram for more than one
   // simultaneous objects with the current infrastructure.
   static bool first_time = true;
   if (first_time) {
     first_time = false;
     // ShouldReportAgain() will re-enter this object.
     if (!size_histogram_.get() && backend->cache_type() == net::DISK_CACHE &&
         backend->ShouldReportAgain()) {
       // Stats may be reused when the cache is re-created, but we want only one
       // histogram at any given time.
-      size_histogram_.reset(new StatsHistogram("DiskCache.SizeStats"));
+      size_histogram_ =
+          StatsHistogram::StatsHistogramFactoryGet("DiskCache.SizeStats");
       size_histogram_->Init(this);
     }
   }
 
   return true;
 }
 
 Stats::~Stats() {
   Store();
 }
@@ skipping 159 matching lines @@
   stats.signature = kDiskSignature;
   stats.size = sizeof(stats);
   memcpy(stats.data_sizes, data_sizes_, sizeof(data_sizes_));
   memcpy(stats.counters, counters_, sizeof(counters_));
 
   Addr address(storage_addr_);
   StoreStats(backend_, address, &stats);
 }
 
 }  // namespace disk_cache