Add metrics for interactions with the Apps Launcher promo dialog.

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

Index: chrome/browser/ui/webui/ntp/app_launcher_handler.h
diff --git a/chrome/browser/ui/webui/ntp/app_launcher_handler.h b/chrome/browser/ui/webui/ntp/app_launcher_handler.h
index 986d055b0cc7f35068c6fb3ca19ccd69bcd64755..7f98ad540f332f4deb8dc0b1383beab7d6670cec 100644
--- a/chrome/browser/ui/webui/ntp/app_launcher_handler.h
+++ b/chrome/browser/ui/webui/ntp/app_launcher_handler.h
@@ -103,6 +103,9 @@ class AppLauncherHandler : public content::WebUIMessageHandler,
   // Callback for "stopShowingAppLauncherPromo" message.
   void StopShowingAppLauncherPromo(const base::ListValue* args);
 
+  // Callback for "onLearnMore" message.
+  void OnLearnMore(const base::ListValue* args);

[miket_OOO, 2013/06/25 15:57:25]

I know you were just following the pattern, but these comments don't tell the
reader anything, and they're subject to copy/paste errors.

[MAD, 2013/06/26 03:33:40]

Done.

+
   // Callback for "closeNotification" message.
   void HandleNotificationClose(const base::ListValue* args);