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

net/disk_cache/histogram_macros.h

 // 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.
 
 // This file contains macros to simplify histogram reporting from the disk
 // cache. The main issue is that we want to have separate histograms for each
 // type of cache (regular vs. media, etc), without adding the complexity of
 // keeping track of a potentially large number of histogram objects that have to
 // survive the backend object that created them.
 
 #ifndef NET_DISK_CACHE_HISTOGRAM_MACROS_H_
 #define NET_DISK_CACHE_HISTOGRAM_MACROS_H_
 
 // HISTOGRAM_HOURS will collect time related data with a granularity of hours
 // and normal values of a few months.
 #define UMA_HISTOGRAM_HOURS UMA_HISTOGRAM_COUNTS_10000
 
 // HISTOGRAM_AGE will collect time elapsed since |initial_time|, with a
 // granularity of hours and normal values of a few months.
 #define UMA_HISTOGRAM_AGE(name, initial_time)\
     UMA_HISTOGRAM_COUNTS_10000(name, (Time::Now() - initial_time).InHours())
 
 // HISTOGRAM_AGE_MS will collect time elapsed since |initial_time|, with the
 // normal resolution of the UMA_HISTOGRAM_TIMES.
 #define UMA_HISTOGRAM_AGE_MS(name, initial_time)\
     UMA_HISTOGRAM_TIMES(name, Time::Now() - initial_time)
 
 #define UMA_HISTOGRAM_CACHE_ERROR(name, sample) do { \
-    static LinearHistogram counter((name), 0, 49, 50); \
-    counter.SetFlags(kUmaTargetedHistogramFlag); \
-    counter.Add(sample); \
+    static scoped_refptr<Histogram> counter = \
+        LinearHistogram::LinearHistogramFactoryGet(\
+            (name), 1, 49, 50); \
+    counter->SetFlags(kUmaTargetedHistogramFlag); \
+    counter->Add(sample); \
   } while (0)
 
 #ifdef NET_DISK_CACHE_BACKEND_IMPL_CC_
 #define BACKEND_OBJ this
 #else
 #define BACKEND_OBJ backend_
 #endif
 
 // Generates a UMA histogram of the given type, generating the proper name for
 // it (asking backend_->HistogramName), and adding the provided sample.
@@ skipping 14 matching lines @@
       case net::MEDIA_CACHE:\
         UMA_HISTOGRAM_##type(my_name.data(), sample);\
         break;\
       default:\
         NOTREACHED();\
         break;\
     }\
   }
 
 #endif  // NET_DISK_CACHE_HISTOGRAM_MACROS_H_