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

net/base/connection_type_histograms.cc

 // Copyright (c) 2009 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/base/connection_type_histograms.h"
 
 #include "base/histogram.h"
 
 namespace net {
 
 // We're using a histogram as a group of counters.  We're only interested in
 // the values of the counters.  Ignore the shape, average, and standard
 // deviation of the histograms because they are meaningless.
 //
 // We use two groups of counters.  In the first group (counter1), each counter
 // is a boolean (0 or 1) that indicates whether the user has seen a connection
 // of that type during that session.  In the second group (counter2), each
 // counter is the number of connections of that type the user has seen during
 // that session.
 //
 // Each histogram has an unused bucket at the end to allow seamless future
 // expansion.
 void UpdateConnectionTypeHistograms(ConnectionType type) {
   static bool had_connection_type[NUM_OF_CONNECTION_TYPES];
-  static LinearHistogram counter1("Net.HadConnectionType",
-                                  1, NUM_OF_CONNECTION_TYPES,
-                                  NUM_OF_CONNECTION_TYPES + 1);
-  static LinearHistogram counter2("Net.ConnectionTypeCount",
-                                  1, NUM_OF_CONNECTION_TYPES,
-                                  NUM_OF_CONNECTION_TYPES + 1);
+  static scoped_refptr<Histogram> counter1 =
+      LinearHistogram::LinearHistogramFactoryGet("Net.HadConnectionType",
+                                                 1, NUM_OF_CONNECTION_TYPES,
+                                                 NUM_OF_CONNECTION_TYPES + 1);
+  static scoped_refptr<Histogram> counter2 =
+      LinearHistogram::LinearHistogramFactoryGet("Net.ConnectionTypeCount",
+                                                 1, NUM_OF_CONNECTION_TYPES,
+                                                 NUM_OF_CONNECTION_TYPES + 1);
 
   if (type >= 0 && type < NUM_OF_CONNECTION_TYPES) {
     if (!had_connection_type[type]) {
       had_connection_type[type] = true;
-      counter1.SetFlags(kUmaTargetedHistogramFlag);
-      counter1.Add(type);
+      counter1->SetFlags(kUmaTargetedHistogramFlag);
+      counter1->Add(type);
     }
   }
-  counter2.SetFlags(kUmaTargetedHistogramFlag);
-  counter2.Add(type);
+  counter2->SetFlags(kUmaTargetedHistogramFlag);
+  counter2->Add(type);
 }
 
 }  // namespace net