Add theme promo to NTP

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
===================================================================
--- chrome/common/pref_names.cc	(revision 26789)
+++ chrome/common/pref_names.cc	(working copy)
@@ -273,6 +273,11 @@
 // directly from the omnibox should be shown.
 const wchar_t kShowOmniboxSearchHint[] = L"browser.show_omnibox_search_hint";
 
+// Integer that counts the number of times the theme promo has left to be
+// shown; this decrements each time the NTP is shown for the first time
+// in a session.
+const wchar_t kNTPThemePromoRemaining[] = L"browser.ntp.theme_promo_remaining";
+
 // *************** LOCAL STATE ***************
 // These are attached to the machine/installation