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

chrome/browser/android/download/download_manager_service.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_DOWNLOAD_DOWNLOAD_MANAGER_SERVICE_H_
 #define CHROME_BROWSER_ANDROID_DOWNLOAD_DOWNLOAD_MANAGER_SERVICE_H_
 
 #include <jni.h>
 #include <map>
 #include <string>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/memory/singleton.h"
 #include "chrome/browser/android/download/download_controller.h"
 #include "chrome/browser/download/all_download_item_notifier.h"
 #include "chrome/browser/download/download_history.h"
 #include "content/public/browser/download_manager.h"
 
 using base::android::JavaParamRef;
 
 namespace content {
 class DownloadItem;
 }
 
 // Native side of DownloadManagerService.java. The native object is owned by its
 // Java object.
 class DownloadManagerService : public AllDownloadItemNotifier::Observer,
                                public DownloadHistory::Observer {
  public:
   // JNI registration.
   static bool RegisterDownloadManagerService(JNIEnv* env);
 
   static void OnDownloadCanceled(
       content::DownloadItem* download,
       DownloadController::DownloadCancelReason reason);
 
-  DownloadManagerService(JNIEnv* env,
-                         jobject jobj);
+  static DownloadManagerService* GetInstance();
+
+  DownloadManagerService();
   ~DownloadManagerService() override;
 
+  // Called to Initialize this object.
+  void Init(JNIEnv* env, jobject obj);
+
   // Called to resume downloading the item that has GUID equal to
   // |jdownload_guid|..
   void ResumeDownload(JNIEnv* env,
                       jobject obj,
                       const JavaParamRef<jstring>& jdownload_guid,
                       bool is_off_the_record);
 
   // Called to cancel a download item that has GUID equal to |jdownload_guid|.
   // If the DownloadItem is not yet created, retry after a while.
   void CancelDownload(JNIEnv* env,
@@ skipping 36 matching lines @@
   void OnDownloadRemoved(content::DownloadManager* manager,
                          content::DownloadItem* item) override;
 
  protected:
   // Called to get the content::DownloadManager instance.
   virtual content::DownloadManager* GetDownloadManager(bool is_off_the_record);
 
  private:
   // For testing.
   friend class DownloadManagerServiceTest;
+  friend struct base::DefaultSingletonTraits<DownloadManagerService>;
 
   // Helper function to start the download resumption.
   void ResumeDownloadInternal(const std::string& download_guid,
                               bool is_off_the_record);
 
   // Helper function to cancel a download.
   void CancelDownloadInternal(const std::string& download_guid,
                               bool is_off_the_record);
 
   // Helper function to pause a download.
@@ skipping 39 matching lines @@
 
   ResumeCallback resume_callback_for_testing_;
 
   std::unique_ptr<AllDownloadItemNotifier> original_notifier_;
   std::unique_ptr<AllDownloadItemNotifier> off_the_record_notifier_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadManagerService);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_DOWNLOAD_DOWNLOAD_MANAGER_SERVICE_H_