Don't warmup the app list if it hasn't been used in the past 28 days. [Win]

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 14f58d57a3230785f2d423ddaf1fcb3d458a6708..fb50cb121aeddbce4ddb4ff8cd4515d390596a42 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -2179,6 +2179,9 @@ const char kAppListEnableMethod[] = "app_list.how_enabled";
 // The time that the app launcher was enabled. Cleared when UMA is recorded.
 const char kAppListEnableTime[] = "app_list.when_enabled";
 
+// The last time the app list was launched.
+const char kAppListLastLaunchTime[] = "app_list.last_launch";
+
 // Integer representing the version of the app launcher shortcut installed on
 // the system. Incremented, e.g., when embedded icons change.
 const char kAppLauncherShortcutVersion[] = "apps.app_launcher.shortcut_version";