Handle early pause, cancel for parallel requests.

content/browser/download/download_worker.h

 // Copyright 2017 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 CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_WORKER_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_WORKER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "content/browser/byte_stream.h"
 #include "content/browser/download/download_request_handle.h"
 #include "content/browser/download/url_downloader.h"
+#include "content/common/content_export.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/download_url_parameters.h"
 
 namespace content {
 
 // Helper class used to send subsequent range requests to fetch slices of the
 // file after handling response of the original non-range request.
 // TODO(xingliu): we should consider to reuse this class for single connection
 // download.
-class DownloadWorker : public UrlDownloader::Delegate {
+class CONTENT_EXPORT DownloadWorker : public UrlDownloader::Delegate {
  public:
   class Delegate {
    public:
     // Called when the the byte stream is established after server response is
     // handled. The stream contains data starts from |offset| of the
     // destination file.
     virtual void OnByteStreamReady(
         DownloadWorker* worker,
         std::unique_ptr<ByteStreamReader> stream_reader) = 0;
     // Called when there is an error caused by the server response.
@@ skipping 30 matching lines @@
           downloader);
 
   DownloadWorker::Delegate* const delegate_;
 
   // The starting position of the content for this worker to download.
   int64_t offset_;
 
   // The length of the request. May be 0 to fetch to the end of the file.
   int64_t length_;
 
+  // States of the worker.
+  bool is_paused_;
+  bool is_canceled_;
+
   // Used to control the network request. Live on UI thread.
   std::unique_ptr<DownloadRequestHandleInterface> request_handle_;
 
   // Used to handle the url request. Live and die on IO thread.
   std::unique_ptr<UrlDownloader, BrowserThread::DeleteOnIOThread>
       url_downloader_;
 
   base::WeakPtrFactory<DownloadWorker> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadWorker);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_WORKER_H_