Add webui handler for promotions on Android NTP.

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 c5e94f6305878b9c8befd5a2d9f27e02a39fe0a0..4cc9defffa10a607fc44a90fecbbf2b142422f66 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1479,6 +1479,9 @@ const char kNtpPromoVersion[] = "ntp.promo_version";
 // The last locale the promo was fetched for.
 const char kNtpPromoLocale[] = "ntp.promo_locale";
 
+// True if a desktop sync session was found for this user.
+const char kNtpPromoDesktopSessionFound[] = "ntp.promo_desktop_session_found";
+
 // Boolean indicating whether the web store is active for the current locale.
 const char kNtpWebStoreEnabled[] = "ntp.webstore_enabled";