Ask download manager to remove a download if it is overwritten by another

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 47 matching lines @@
   bool has_no_external_storage =
       (reason == DownloadController::CANCEL_REASON_NO_EXTERNAL_STORAGE);
   JNIEnv* env = base::android::AttachCurrentThread();
   ScopedJavaLocalRef<jstring> jname =
       ConvertUTF8ToJavaString(env, download->GetURL().ExtractFileName());
   Java_DownloadManagerService_onDownloadItemCanceled(env, jname,
                                                      has_no_external_storage);
   DownloadController::RecordDownloadCancelReason(reason);
 }
 
+// static
+DownloadManagerService* DownloadManagerService::GetInstance() {
+  return base::Singleton<DownloadManagerService>::get();
+}
 
 static jlong Init(JNIEnv* env, const JavaParamRef<jobject>& jobj) {
   Profile* profile = ProfileManager::GetActiveUserProfile();
-  DownloadManagerService* service =
-      new DownloadManagerService(env, jobj);
+  DownloadManagerService* service = DownloadManagerService::GetInstance();
+  service->Init(env, jobj);
   DownloadService* download_service =
       DownloadServiceFactory::GetForBrowserContext(profile);
   DownloadHistory* history = download_service->GetDownloadHistory();
   if (history)
     history->AddObserver(service);
   return reinterpret_cast<intptr_t>(service);
 }
 
-DownloadManagerService::DownloadManagerService(
+DownloadManagerService::DownloadManagerService()
+    : is_history_query_complete_(false) {
+}
+
+DownloadManagerService::~DownloadManagerService() {}
+
+void DownloadManagerService::Init(
     JNIEnv* env,
-    jobject obj)
-    : java_ref_(env, obj),
-      is_history_query_complete_(false) {
+    jobject obj) {
+  java_ref_.Reset(env, obj);
   DownloadControllerBase::Get()->SetDefaultDownloadFileName(
       l10n_util::GetStringUTF8(IDS_DEFAULT_DOWNLOAD_FILENAME));
 }
 
-DownloadManagerService::~DownloadManagerService() {}
-
 void DownloadManagerService::ResumeDownload(
     JNIEnv* env,
     jobject obj,
     const JavaParamRef<jstring>& jdownload_guid,
     bool is_off_the_record) {
   std::string download_guid = ConvertJavaStringToUTF8(env, jdownload_guid);
   if (is_history_query_complete_ || is_off_the_record)
     ResumeDownloadInternal(download_guid, is_off_the_record);
   else
     EnqueueDownloadAction(download_guid, RESUME);
@@ skipping 287 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;
 }