Downloads: replace BrowserThread::FILE with task scheduler.

content/browser/download/download_file_impl.h

 // Copyright (c) 2012 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_FILE_IMPL_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_
 
 #include "content/browser/download/download_file.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <unordered_map>
 #include <vector>
 
 #include "base/files/file.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
-#include "base/threading/thread_checker.h"
+#include "base/sequence_checker.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "content/browser/byte_stream.h"
 #include "content/browser/download/base_file.h"
 #include "content/browser/download/rate_estimator.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_save_info.h"
 #include "net/log/net_log_with_source.h"
 
 namespace content {
 class ByteStreamReader;
 class DownloadDestinationObserver;
 
 class CONTENT_EXPORT DownloadFileImpl : public DownloadFile {
  public:
   // Takes ownership of the object pointed to by |request_handle|.
   // |net_log| will be used for logging the download file's events.
   // May be constructed on any thread.  All methods besides the constructor
-  // (including destruction) must occur on the FILE thread.
+  // (including destruction) must occur in the same sequence.
   //
   // Note that the DownloadFileImpl automatically reads from the passed in
   // stream, and sends updates and status of those reads to the
   // DownloadDestinationObserver.
-  DownloadFileImpl(
-      std::unique_ptr<DownloadSaveInfo> save_info,
-      const base::FilePath& default_downloads_directory,
-      std::unique_ptr<ByteStreamReader> stream_reader,
-      const net::NetLogWithSource& net_log,
-      base::WeakPtr<DownloadDestinationObserver> observer);
+  DownloadFileImpl(std::unique_ptr<DownloadSaveInfo> save_info,
+                   const base::FilePath& default_downloads_directory,
+                   std::unique_ptr<ByteStreamReader> stream_reader,
+                   const net::NetLogWithSource& net_log,
+                   base::WeakPtr<DownloadDestinationObserver> observer);
 
   ~DownloadFileImpl() override;
 
   // DownloadFile functions.
   void Initialize(const InitializeCallback& initialize_callback,
                   const CancelRequestCallback& cancel_request_callback,
                   const DownloadItem::ReceivedSlices& received_slices,
                   bool is_parallelizable) override;
 
   void AddByteStream(std::unique_ptr<ByteStreamReader> stream_reader,
@@ skipping 174 matching lines @@
   // Print the internal states for debugging.
   void DebugStates() const;
 
   net::NetLogWithSource net_log_;
 
   // The base file instance.
   BaseFile file_;
 
   // DownloadSaveInfo provided during construction. Since the DownloadFileImpl
   // can be created on any thread, this holds the save_info_ until it can be
-  // used to initialize file_ on the FILE thread.
+  // used to initialize file_ on the download sequence.
   std::unique_ptr<DownloadSaveInfo> save_info_;
 
   // The default directory for creating the download file.
   base::FilePath default_download_directory_;
 
   // Map of the offset and the source stream that represents the slice
   // starting from offset.
   SourceStreams source_streams_;
 
   // Used to cancel the request on UI thread, since the ByteStreamReader can't
@@ skipping 15 matching lines @@
   int num_active_streams_;
   bool record_stream_bandwidth_;
   base::TimeTicks last_update_time_;
   size_t bytes_seen_with_parallel_streams_;
   size_t bytes_seen_without_parallel_streams_;
   base::TimeDelta download_time_with_parallel_streams_;
   base::TimeDelta download_time_without_parallel_streams_;
 
   std::vector<DownloadItem::ReceivedSlice> received_slices_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   base::WeakPtr<DownloadDestinationObserver> observer_;
   base::WeakPtrFactory<DownloadFileImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadFileImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_IMPL_H_