Fix a crash when downloading a dangerous download

chrome/browser/android/download/download_controller.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/download/download_controller.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/android/context_utils.h"
@@ skipping 225 matching lines @@
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   WebContents* web_contents = download_item->GetWebContents();
   if (!web_contents)
     return;
 
   // Register for updates to the DownloadItem.
   download_item->AddObserver(this);
 
   ChromeDownloadDelegate* delegate =
       ChromeDownloadDelegate::FromWebContents(web_contents);
-  if (delegate) {
+  // For dangerous item, we need to show the dangerous infobar before the
+  // download can start.
+  if (!download_item->IsDangerous() && delegate) {
     delegate->OnDownloadStarted(
         download_item->GetTargetFilePath().BaseName().value());
   }
   OnDownloadUpdated(download_item);
 }
 
 void DownloadController::OnDownloadUpdated(DownloadItem* item) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (item->IsDangerous() && (item->GetState() != DownloadItem::CANCELLED)) {
     // Dont't show notification for a dangerous download, as user can resume
@@ skipping 70 matching lines @@
 void DownloadController::StartContextMenuDownload(
     const ContextMenuParams& params, WebContents* web_contents, bool is_link,
     const std::string& extra_headers) {
   int process_id = web_contents->GetRenderProcessHost()->GetID();
   int routing_id = web_contents->GetRenderViewHost()->GetRoutingID();
   AcquireFileAccessPermission(
       web_contents, base::Bind(&CreateContextMenuDownload, process_id,
                                routing_id, params, is_link, extra_headers));
 }