Add field to monitor last visited time for each search engine

components/search_engines/template_url_service.h

Index: components/search_engines/template_url_service.h
diff --git a/components/search_engines/template_url_service.h b/components/search_engines/template_url_service.h
index 801ca6364295522dc093aff93e476256ab2f7a01..2ebf9147b63e24242a534a532eb4da7e8b7c9a37 100644
--- a/components/search_engines/template_url_service.h
+++ b/components/search_engines/template_url_service.h
@@ -288,6 +288,9 @@ class TemplateURLService : public WebDataServiceConsumer,
   // prepopulate data.
   void RepairPrepopulatedSearchEngines();
 
+  // Update the last_visited time of TemplateURL to current time.

[Peter Kasting, 2016/11/21 03:35:08]

Nit: Comments should be declarative ("Updates") rather than imperative
("Update"); see
http://google.github.io/styleguide/cppguide.html#Function_Comments

Also, "current" -> "the current"

[ltian, 2016/11/28 22:08:02]

Done.

+  void UpdateTemplateURLVisitTime(TemplateURL* url);
+
   // Observers used to listen for changes to the model.
   // TemplateURLService does NOT delete the observers when deleted.
   void AddObserver(TemplateURLServiceObserver* observer);