Revert of DataReductionProxyStatisticsPrefs should support WeakPtr

components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.cc

Index: components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.cc
diff --git a/components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.cc b/components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.cc
index 2dba43560d14529ab3e0a165e33c6e542aeb1e54..26fad478e18f7411bbebe146fa19f8d22395c8fa 100644
--- a/components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.cc
+++ b/components/data_reduction_proxy/core/browser/data_reduction_proxy_settings.cc
@@ -128,17 +128,14 @@
 
 void DataReductionProxySettings::InitDataReductionProxySettings(
     PrefService* prefs,
-    scoped_ptr<DataReductionProxyStatisticsPrefs> statistics_prefs,
     net::URLRequestContextGetter* url_request_context_getter,
     net::NetLog* net_log,
     DataReductionProxyEventStore* event_store) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(prefs);
-  DCHECK(!statistics_prefs_);
   DCHECK(url_request_context_getter);
   DCHECK(event_store);
   prefs_ = prefs;
-  statistics_prefs_ = statistics_prefs.Pass();
   url_request_context_getter_ = url_request_context_getter;
   net_log_ = net_log;
   event_store_ = event_store;
@@ -154,25 +151,8 @@
 }
 
 void DataReductionProxySettings::SetDataReductionProxyStatisticsPrefs(
-    scoped_ptr<DataReductionProxyStatisticsPrefs> statistics_prefs) {
-  statistics_prefs_ = statistics_prefs.Pass();
-}
-
-void DataReductionProxySettings::EnableCompressionStatisticsLogging(
-    PrefService* prefs,
-    scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
-    const base::TimeDelta& commit_delay) {
-  DCHECK(!statistics_prefs_);
-  statistics_prefs_.reset(
-      new DataReductionProxyStatisticsPrefs(
-          prefs, ui_task_runner, commit_delay));
-}
-
-base::WeakPtr<DataReductionProxyStatisticsPrefs>
-DataReductionProxySettings::statistics_prefs() {
-  if (statistics_prefs_)
-    return statistics_prefs_->GetWeakPtr();
-  return base::WeakPtr<DataReductionProxyStatisticsPrefs>();
+    DataReductionProxyStatisticsPrefs* statistics_prefs) {
+  statistics_prefs_ = statistics_prefs;
 }
 
 void DataReductionProxySettings::SetOnDataReductionEnabledCallback(