Update from https://crrev.com/333737

base/prefs/json_pref_store.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 "base/prefs/json_pref_store.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 285 matching lines @@
       FROM_HERE,
       base::Bind(&ReadPrefsFromDisk, path_, alternate_path_),
       base::Bind(&JsonPrefStore::OnFileRead, AsWeakPtr()));
 }
 
 void JsonPrefStore::CommitPendingWrite() {
   DCHECK(CalledOnValidThread());
 
   // Schedule a write for any lossy writes that are outstanding to ensure that
   // they get flushed when this function is called.
-  if (pending_lossy_write_)
-    writer_.ScheduleWrite(this);
+  SchedulePendingLossyWrites();
 
   if (writer_.HasPendingWrite() && !read_only_)
     writer_.DoScheduledWrite();
 }
 
+void JsonPrefStore::SchedulePendingLossyWrites() {
+  if (pending_lossy_write_)
+    writer_.ScheduleWrite(this);
+}
+
 void JsonPrefStore::ReportValueChanged(const std::string& key, uint32 flags) {
   DCHECK(CalledOnValidThread());
 
   if (pref_filter_)
     pref_filter_->FilterUpdate(key);
 
   FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
 
   ScheduleWrite(flags);
 }
@@ skipping 210 matching lines @@
   DCHECK_EQ(31, num_buckets);
 
   // The histogram below is an expansion of the UMA_HISTOGRAM_CUSTOM_COUNTS
   // macro adapted to allow for a dynamically suffixed histogram name.
   // Note: The factory creates and owns the histogram.
   base::HistogramBase* histogram = base::Histogram::FactoryGet(
       histogram_name, min_value, max_value, num_buckets,
       base::HistogramBase::kUmaTargetedHistogramFlag);
   return histogram;
 }