Added last_modified field to TemplateURL and database. Updated unit tests, including refactoring ...

chrome/browser/search_engines/template_url.h

Index: chrome/browser/search_engines/template_url.h
===================================================================
--- chrome/browser/search_engines/template_url.h	(revision 90021)
+++ chrome/browser/search_engines/template_url.h	(working copy)
@@ -425,6 +425,12 @@
   void set_date_created(base::Time time) { date_created_ = time; }
   base::Time date_created() const { return date_created_; }
 
+  // The last time this keyword was modified by a user, since creation.
+  //
+  // NOTE: Like date_created above, this may be 0.
+  void set_last_modified(base::Time time) { last_modified_ = time; }
+  base::Time last_modified() const { return last_modified_; }
+
   // True if this TemplateURL was automatically created by the administrator via
   // group policy.
   void set_created_by_policy(bool created_by_policy) {
@@ -510,6 +516,7 @@
   std::vector<std::string> input_encodings_;
   TemplateURLID id_;
   base::Time date_created_;
+  base::Time last_modified_;
   bool created_by_policy_;
   int usage_count_;
   SearchEngineType search_engine_type_;