Fixed a crash in auto-resumption handler

Bug: 987052
Change-Id: Ibd4178eac4fd22d53f6bf80607fbbdecdd94378c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1715728Reviewed-by: Min Qin <qinmin@chromium.org>
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680492}

components/download/public/common/auto_resumption_handler.cc

@@ -268,7 +268,7 @@ bool AutoResumptionHandler::SatisfiesNetworkRequirements(
 
 bool AutoResumptionHandler::IsAutoResumableDownload(
     download::DownloadItem* item) {
-  if (item->IsDangerous())
+  if (!item || item->IsDangerous())
     return false;
 
   switch (item->GetState()) {