alternate ntp: implement searchbox api for instant overlay to adopt themes

chrome/common/chrome_notification_types.h

Index: chrome/common/chrome_notification_types.h
diff --git a/chrome/common/chrome_notification_types.h b/chrome/common/chrome_notification_types.h
index 90e8f18f991abfb5024ee317955c89ae652301bf..fc387c69a13db234875e3a99fb736a1f316fe9d7 100644
--- a/chrome/common/chrome_notification_types.h
+++ b/chrome/common/chrome_notification_types.h
@@ -1244,12 +1244,6 @@ enum NotificationType {
   // if it is leaving.
   NOTIFICATION_CONTENT_BLOCKED_STATE_CHANGED,
 
-  // SearchViewController.
-  // Sent when animations initiated by search view controller complete.
-  // The source is the SearchViewController whose animation is finished.
-  // No details.
-  NOTIFICATION_SEARCH_VIEW_CONTROLLER_ANIMATION_FINISHED,
-
   // Note:-
   // Currently only Content and Chrome define and use notifications.
   // Custom notifications not belonging to Content and Chrome should start