Make ShortcutsBackend a ProfileKeyedService.

chrome/browser/history/shortcuts_backend.cc

Index: chrome/browser/history/shortcuts_backend.cc
===================================================================
--- chrome/browser/history/shortcuts_backend.cc	(revision 144929)
+++ chrome/browser/history/shortcuts_backend.cc	(working copy)
@@ -81,11 +81,11 @@
 
 // ShortcutsBackend -----------------------------------------------------------
 
-ShortcutsBackend::ShortcutsBackend(const FilePath& db_folder_path,
-                                   Profile *profile)
+ShortcutsBackend::ShortcutsBackend(Profile* profile, bool suppress_db)
     : current_state_(NOT_INITIALIZED),
-      db_(new ShortcutsDatabase(db_folder_path)),
-      no_db_access_(db_folder_path.empty()) {
+      no_db_access_(suppress_db) {
+  if (!suppress_db)
+    db_ = new ShortcutsDatabase(profile);
   // |profile| can be NULL in tests.
   if (profile) {
     notification_registrar_.Add(this, chrome::NOTIFICATION_OMNIBOX_OPENED_URL,
@@ -264,4 +264,10 @@
       match.description_class, base::Time::Now(), 1));
 }
 
+void ShortcutsBackend::ShutdownOnUIThread() {
+  DCHECK(!BrowserThread::IsWellKnownThread(BrowserThread::UI) ||
+         BrowserThread::CurrentlyOn(BrowserThread::UI));
+  notification_registrar_.RemoveAll();
+}
+
 }  // namespace history