[Downloads] Remove externally deleted items from downloads history

chrome/browser/android/download/download_manager_service.cc

 // Copyright 2015 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_manager_service.h"
 
 #include "base/android/jni_string.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 156 matching lines @@
 
   Java_DownloadManagerService_onAllDownloadsRetrieved(
       env, java_ref_, j_download_item_list, is_off_the_record);
 }
 
 void DownloadManagerService::CheckForExternallyRemovedDownloads(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj,
     bool is_off_the_record) {
   content::DownloadManager* manager = GetDownloadManager(is_off_the_record);
-  if (!manager)
+
+  // Once the history query is complete, download_history.cc will check for the
+  // removal of history files. If the history query is not yet complete, ignore
+  // requests to check for externally removed downloads.
+  if (!manager || !is_history_query_complete_)

[qinmin, 2016/08/24 16:30:53]

Nit: there is no need to get the manager if is_history_query_complete_ is false.

So it would be better to change this to:

if (!is_history_query_complete_) 
  return;

DownloadManger* manager = ....
....

[Theresa, 2016/08/24 22:52:09]

Done.

     return;
   manager->CheckForHistoryFilesRemoval();
 }
 
 void DownloadManagerService::CancelDownload(
     JNIEnv* env,
     jobject obj,
     const JavaParamRef<jstring>& jdownload_guid,
     bool is_off_the_record,
     bool is_notification_dismissed) {
@@ skipping 195 matching lines @@
   content::DownloadManager* manager =
       content::BrowserContext::GetDownloadManager(profile);
 
   // Update notifiers to monitor any newly created DownloadManagers.
   updateNotifier(
       this, manager,
       is_off_the_record ? off_the_record_notifier_ : original_notifier_);
 
   return manager;
 }