[Offline pages] Ensure that download notifications are updated after restart of Chrome

* This patch removes checks for DownloadManagementService to be initialized,
  as it might not have been right after a restart of Chrome.

BUG=641590
R=qinmin@chromium.org

Review-Url: https://codereview.chromium.org/2302423003
Cr-Commit-Position: refs/heads/master@{#416366}

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/downloads/OfflinePageNotificationBridge.java

@@ -139,7 +139,6 @@ public class OfflinePageNotificationBridge {
     }
 
     private static DownloadNotifier getDownloadNotifier(Context context) {
-        if (!DownloadManagerService.hasDownloadManagerService()) return null;
         return DownloadManagerService.getDownloadManagerService(context).getDownloadNotifier();
     }
 }