NTP4/Sync Promo:

chrome/browser/ui/webui/ntp/ntp_login_handler.h

Index: chrome/browser/ui/webui/ntp/ntp_login_handler.h
diff --git a/chrome/browser/ui/webui/ntp/ntp_login_handler.h b/chrome/browser/ui/webui/ntp/ntp_login_handler.h
index 3169ba098f7f6544aa7fcd334e83ae995ff4b887..890a34c9d9a3fe45633d650cc0c65af456318cbc 100644
--- a/chrome/browser/ui/webui/ntp/ntp_login_handler.h
+++ b/chrome/browser/ui/webui/ntp/ntp_login_handler.h
@@ -38,10 +38,10 @@ class NTPLoginHandler : public WebUIMessageHandler,
 
  private:
   // User actions while on the NTP when clicking on or viewing the sync promo.
-  enum SyncPromoNTPPromoBuckets {
-    SYNC_PROMO_NTP_PROMO_VIEWED,
-    SYNC_PROMO_NTP_PROMO_CLICKED,
-    SYNC_PROMO_NTP_PROMO_BUCKET_BOUNDARY,
+  enum NTPSignInPromoBuckets {
+    NTP_SIGN_IN_PROMO_VIEWED,
+    NTP_SIGN_IN_PROMO_CLICKED,
+    NTP_SIGN_IN_PROMO_BUCKET_BOUNDARY,
   };
 
   // Called from JS when the NTP is loaded. |args| is the list of arguments
@@ -53,6 +53,9 @@ class NTPLoginHandler : public WebUIMessageHandler,
   // arguments passed from JS and should be an empty list.
   void HandleShowSyncLoginUI(const ListValue* args);
 
+  // Records actions in SyncPromo.NTPPromo histogram.
+  void RecordInHistogram(int type);
+
   // Internal helper method
   void UpdateLogin();