[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 58 matching lines @@
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jstring>& jquery,
       const base::android::JavaParamRef<jstring>& jalternate_term,
       jboolean jshould_prefetch,
       const base::android::JavaParamRef<jstring>& jprotocol_version);
   base::android::ScopedJavaLocalRef<jstring> GetSearchEngineUrlFromTemplateUrl(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jstring>& jkeyword);
+  base::android::ScopedJavaLocalRef<jstring> AddSearchEngineForTesting(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jstring>& jkeyword,
+      jint age_in_days);
+  base::android::ScopedJavaLocalRef<jstring> UpdateLastVisitedForTesting(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jstring>& jkeyword);
 
   static bool Register(JNIEnv* env);
 
  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 descending
+  // order.
   void LoadTemplateURLs();
 
   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_