Add field to monitor last visited time for each search engine

components/search_engines/template_url_data.h

Index: components/search_engines/template_url_data.h
diff --git a/components/search_engines/template_url_data.h b/components/search_engines/template_url_data.h
index 4b3479a96a2f37af235677ea082bff077a2410e0..93088a8dbdf3420d724791916160964cfc209351 100644
--- a/components/search_engines/template_url_data.h
+++ b/components/search_engines/template_url_data.h
@@ -110,6 +110,11 @@ struct TemplateURLData {
   // NOTE: Like date_created above, this may be 0.
   base::Time last_modified;
 
+  // Date when this TemplateURL was last visited.
+  //
+  // NOTE: This might be 0 if the TemplateURL has never been visited.
+  base::Time last_visited;
+
   // True if this TemplateURL was automatically created by the administrator via
   // group policy.
   bool created_by_policy;