Use lock-free lazy initialization for static histogram references

webkit/glue/webkitclient_impl.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 "webkit/glue/webkitclient_impl.h"
 
 #if defined(OS_LINUX)
 #include <malloc.h>
 #endif
 
@@ skipping 246 matching lines @@
 }
 
 void WebKitClientImpl::incrementStatsCounter(const char* name) {
   base::StatsCounter(name).Increment();
 }
 
 void WebKitClientImpl::histogramCustomCounts(
     const char* name, int sample, int min, int max, int bucket_count) {
   // Copied from histogram macro, but without the static variable caching
   // the histogram because name is dynamic.
-  scoped_refptr<base::Histogram> counter =
+  base::Histogram* counter =
       base::Histogram::FactoryGet(name, min, max, bucket_count,
           base::Histogram::kUmaTargetedHistogramFlag);
   DCHECK_EQ(name, counter->histogram_name());
-  if (counter.get())
-    counter->Add(sample);
+  counter->Add(sample);
 }
 
 void WebKitClientImpl::histogramEnumeration(
     const char* name, int sample, int boundary_value) {
   // Copied from histogram macro, but without the static variable caching
   // the histogram because name is dynamic.
-  scoped_refptr<base::Histogram> counter =
+  base::Histogram* counter =
       base::LinearHistogram::FactoryGet(name, 1, boundary_value,
           boundary_value + 1, base::Histogram::kUmaTargetedHistogramFlag);
   DCHECK_EQ(name, counter->histogram_name());
-  if (counter.get())
-    counter->Add(sample);
+  counter->Add(sample);
 }
 
 void WebKitClientImpl::traceEventBegin(const char* name, void* id,
                                        const char* extra) {
   TRACE_EVENT_BEGIN(name, id, extra);
   GPU_TRACE_EVENT_BEGIN2("webkit", name,
                          "id", StringPrintf("%p", id).c_str(),
                          "extra", extra ? extra : "");
 }
 
@@ skipping 303 matching lines @@
   ++shared_timer_suspended_;
 }
 
 void WebKitClientImpl::ResumeSharedTimer() {
   // The shared timer may have fired or been adjusted while we were suspended.
   if (--shared_timer_suspended_ == 0 && !shared_timer_.IsRunning())
     setSharedTimerFireTime(shared_timer_fire_time_);
 }
 
 }  // namespace webkit_glue