Added pref for snapshot document collapsed state

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 3bbb6903485cf3ad21c7f172c145651eee8b8db1..3354b75021cebda8984190db4041b83cc1b87294 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1709,6 +1709,17 @@ const char kExtensionStorageGarbageCollect[] =
 // Keeps track of which sessions are collapsed in the Other Devices menu.
 const char kNtpCollapsedForeignSessions[] = "ntp.collapsed_foreign_sessions";
 
+// Keeps track of snapshot documents collapsed state in the Other Devices menu.
+const char kNtpCollapsedSnapshotDocument[] = "ntp.collapsed_snapshot_document";
+
+// Keeps track of recently closed tabs collapsed state in the Other Devices
+// menu.
+const char kNtpCollapsedRecentlyClosedTabs[] =
+    "ntp.collapsed_recently_closed_tabs";
+
+// Keeps track of sync promo collapsed state in the Other Devices menu.
+const char kNtpCollapsedSyncPromo[] = "ntp.collapsed_sync_promo";
+
 // New Tab Page URLs that should not be shown as most visited thumbnails.
 const char kNtpMostVisitedURLsBlacklist[] = "ntp.most_visited_blacklist";