[Android] Sort custom search engines based on last visited time and display only top 3 most recentl…

chrome/browser/search_engines/template_url_service_android.h

 // Copyright (c) 2013 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.
 
 #ifndef CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_ANDROID_H_
 #define CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_ANDROID_H_
 
 #include <memory>
 
 #include "base/android/jni_weak_ref.h"
@@ skipping 71 matching lines @@
  private:
   ~TemplateUrlServiceAndroid() override;
 
   void OnTemplateURLServiceLoaded();
 
   // TemplateUrlServiceObserver:
   void OnTemplateURLServiceChanged() override;
 
   // Updates |template_urls_| to contain all TemplateURLs.  It sorts this list
   // with prepopulated engines first, then any default non-prepopulated engine,
-  // then other non-prepopulated engines.
+  // then other non-prepopulated engines based on last_visited in the

[Peter Kasting, 2016/12/06 06:24:55]

Nit: remove "the"

[ltian, 2016/12/07 00:56:43]

Done.

+  // descending order.
   void LoadTemplateURLs();
 
+  // Counts the number of custom search engine needed to be remove from
+  // |template_urls_|. Android only shows top 5 most recently visited engines,
+  // the rest of custom search engine will be removed from |template_urls_|.
+  int CountRemovedSearchEngineNum();
+
   JavaObjectWeakGlobalRef weak_java_obj_;
 
   // Pointer to the TemplateUrlService for the main profile.
   TemplateURLService* template_url_service_;
 
   std::unique_ptr<TemplateURLService::Subscription> template_url_subscription_;
 
   // Caches the up-to-date TemplateURL list so that calls from Android could
   // directly get data from it.
   std::vector<TemplateURL*> template_urls_;
 
   DISALLOW_COPY_AND_ASSIGN(TemplateUrlServiceAndroid);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_ANDROID_H_