Connect SparseHistogram with the rest of stats system

content/browser/histogram_message_filter.cc

 // Copyright (c) 2012 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 "content/browser/histogram_message_filter.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/process_util.h"
@@ skipping 45 matching lines @@
       CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kReduceSecurityForDomAutomationTests);
 
   if (!using_dom_controller || !reduced_security) {
     LOG(ERROR) << "Attempt at reading browser histogram without specifying "
                << "--" << switches::kDomAutomationController << " and "
                << "--" << switches::kReduceSecurityForDomAutomationTests
                << " switches.";
     return;
   }
-  base::Histogram* histogram = base::StatisticsRecorder::FindHistogram(name);
+  base::HistogramBase* histogram =
+      base::StatisticsRecorder::FindHistogram(name);
   if (!histogram) {
     *histogram_json = "{}";
   } else {
     histogram->WriteJSON(histogram_json);
   }
 }
 
 }  // namespace content