Using STL to implement functionality in input_method_util.cc

chrome/browser/spellchecker/spellcheck_service.cc

Index: chrome/browser/spellchecker/spellcheck_service.cc
diff --git a/chrome/browser/spellchecker/spellcheck_service.cc b/chrome/browser/spellchecker/spellcheck_service.cc
index 7360f061548efc9d4258c6ee0d3eac1bec9a3719..374fa2f23e4c4e0d7c5c209b8ce671306581b5a8 100644
--- a/chrome/browser/spellchecker/spellcheck_service.cc
+++ b/chrome/browser/spellchecker/spellcheck_service.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/spellchecker/spellcheck_service.h"
 
+#include <algorithm>
 #include <set>
 
 #include "base/logging.h"
@@ -353,12 +354,11 @@ void SpellcheckService::OnAcceptLanguagesChanged() {
   std::vector<std::string> dictionaries = dictionaries_pref.GetValue();
   std::vector<std::string> filtered_dictionaries;
 
-  for (const auto& dictionary : dictionaries) {
-    if (std::find(accept_languages.begin(), accept_languages.end(),
-                  dictionary) != accept_languages.end()) {
-      filtered_dictionaries.push_back(dictionary);
-    }
-  }
+  std::sort(dictionaries.begin(), dictionaries.end());

[groby-ooo-7-16, 2016/04/04 22:30:40]

Before modifying things, please check the history _why_ it's different from what
you think is the better pattern.

In this case, https://codereview.chromium.org/1673783003 - we cannot change the
order of dictionaries because that affects a preference the user has expressed.

[chakshu, 2016/04/11 06:54:37]

Thank you for the review. 
Using unordered_set will improve the performance so I think it is the better
pattern from what has been done till now.
Now I have also taken care that the order of dictionaries does not change. 

+  std::sort(accept_languages.begin(), accept_languages.end());
+  std::set_intersection(dictionaries.begin(), dictionaries.end(),
+                        accept_languages.begin(), accept_languages.end(),
+                        std::back_inserter(filtered_dictionaries));
 
   dictionaries_pref.SetValue(filtered_dictionaries);
 }