Add field to monitor last visited time for each search engine

components/search_engines/template_url_service.h

 // Copyright 2014 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 COMPONENTS_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_H_
 #define COMPONENTS_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_H_
 
 #include <stddef.h>
 
 #include <list>
@@ skipping 270 matching lines @@
   // revved: all existing prepopulated entries are checked against the current
   // prepopulate data, any now-extraneous safe_for_autoreplace() entries are
   // removed, any existing engines are reset to the provided data (except for
   // user-edited names or keywords), and any new prepopulated engines are
   // added.
   //
   // After this, the default search engine is reset to the default entry in the
   // prepopulate data.
   void RepairPrepopulatedSearchEngines();
 
+  // Updates the last_visited time of TemplateURL to the current time.
+  bool UpdateTemplateURLVisitTime(TemplateURL* url);

[Peter Kasting, 2016/12/01 07:38:25]

This is only public due to being used in a test.  I'm inclined to make it
private instead and FRIEND_TEST the test, as we don't really want any non-test
code calling this.

I don't understand why this function returns a value that no one ever reads.  I
think you must have misunderstood my request that you add an Update() function
that would do UpdateNoNotify() + NotifyObservers(), and instead thought I was
talking about this function, and you added a return value to it?  I'm very
confused, and just trying to go off how there's an extra return value here,
whereas there's no Update() (but maybe you intended to add that in a separate
cleanup patch, which would be fine).

[ltian, 2016/12/01 10:02:58]

Sorry I totally misunderstood of your thought. Will fix it.

+
   // Observers used to listen for changes to the model.
   // TemplateURLService does NOT delete the observers when deleted.
   void AddObserver(TemplateURLServiceObserver* observer);
   void RemoveObserver(TemplateURLServiceObserver* observer);
 
   // Loads the keywords. This has no effect if the keywords have already been
   // loaded.
   // Observers are notified when loading completes via the method
   // OnTemplateURLServiceChanged.
   void Load();
@@ skipping 520 matching lines @@
   // Helper class to manage the default search engine.
   DefaultSearchManager default_search_manager_;
 
   std::unique_ptr<GoogleURLTracker::Subscription>
       google_url_updated_subscription_;
 
   DISALLOW_COPY_AND_ASSIGN(TemplateURLService);
 };
 
 #endif  // COMPONENTS_SEARCH_ENGINES_TEMPLATE_URL_SERVICE_H_