Use lock-free lazy initialization for static histogram references

chrome/renderer/render_thread.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 "chrome/renderer/render_thread.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 780 matching lines @@
   if (gpu_channel_->state() != GpuChannelHost::kConnected)
     return NULL;
 
   return gpu_channel_.get();
 }
 
 static void* CreateHistogram(
     const char *name, int min, int max, size_t buckets) {
   if (min <= 0)
     min = 1;
-  scoped_refptr<base::Histogram> histogram = base::Histogram::FactoryGet(
+  base::Histogram* histogram = base::Histogram::FactoryGet(
       name, min, max, buckets, base::Histogram::kUmaTargetedHistogramFlag);
-  // We'll end up leaking these histograms, unless there is some code hiding in
-  // there to do the dec-ref.
-  // TODO(jar): Handle reference counting in webkit glue.
-  histogram->AddRef();
-  return histogram.get();
+  return histogram;
 }
 
 static void AddHistogramSample(void* hist, int sample) {
   base::Histogram* histogram = static_cast<base::Histogram*>(hist);
   histogram->Add(sample);
 }
 
 void RenderThread::EnsureWebKitInitialized() {
   if (webkit_client_.get())
     return;
@@ skipping 242 matching lines @@
       return true;
   }
 
   return false;
 }
 
 void RenderThread::RegisterExtension(v8::Extension* extension) {
   WebScriptController::registerExtension(extension);
   v8_extensions_.insert(extension->name());
 }