[CleanUp] Use base::STLSetDifference() in place of std::set_difference()

chrome/browser/spellchecker/spellcheck_custom_dictionary.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 "chrome/browser/spellchecker/spellcheck_custom_dictionary.h"
 
 #include <functional>
 
 #include "base/file_util.h"
 #include "base/files/important_file_writer.h"
@@ skipping 430 matching lines @@
 }
 
 void SpellcheckCustomDictionary::Apply(
     const SpellcheckCustomDictionary::Change& dictionary_change) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (!dictionary_change.to_add().empty()) {
     words_.insert(dictionary_change.to_add().begin(),
                   dictionary_change.to_add().end());
   }
   if (!dictionary_change.to_remove().empty()) {
-    WordSet updated_words;
-    std::set_difference(words_.begin(),
-                        words_.end(),
-                        dictionary_change.to_remove().begin(),
-                        dictionary_change.to_remove().end(),
-                        std::inserter(updated_words, updated_words.end()));
+    WordSet updated_words =
+        base::STLSetDifference<WordSet>(words_,
+                                        dictionary_change.to_remove());
     std::swap(words_, updated_words);
   }
 }
 
 void SpellcheckCustomDictionary::Save(
     const SpellcheckCustomDictionary::Change& dictionary_change) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   BrowserThread::PostTask(
       BrowserThread::FILE,
       FROM_HERE,
@@ skipping 63 matching lines @@
 
 void SpellcheckCustomDictionary::Notify(
     const SpellcheckCustomDictionary::Change& dictionary_change) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   if (!IsLoaded() || dictionary_change.empty())
     return;
   FOR_EACH_OBSERVER(Observer,
                     observers_,
                     OnCustomDictionaryChanged(dictionary_change));
 }