Downloads: replace BrowserThread::FILE with task scheduler.

content/browser/download/base_file.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_BASE_FILE_H_
 #define CONTENT_BROWSER_DOWNLOAD_BASE_FILE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/sequence_checker.h"
 #include "base/time/time.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 #include "crypto/secure_hash.h"
 #include "net/base/net_errors.h"
 #include "net/log/net_log_with_source.h"
 #include "url/gurl.h"
 
 namespace content {
 
 // File being downloaded and saved to disk. This is a base class
 // for DownloadFile and SaveFile, which keep more state information. BaseFile
 // considers itself the owner of the physical file and will delete it when the
 // BaseFile object is destroyed unless the ownership is revoked via a call to
 // Detach().
 class CONTENT_EXPORT BaseFile {
  public:
   // May be constructed on any thread.  All other routines (including
-  // destruction) must occur on the FILE thread.
+  // destruction) must occur on the download task runner.

[gab, 2017/06/21 19:42:24]

"on the same sequence"

[Sigurður Ásgeirsson, 2017/06/22 14:50:06]

Done.

   BaseFile(const net::NetLogWithSource& net_log);
   ~BaseFile();
 
   // Returns DOWNLOAD_INTERRUPT_REASON_NONE on success, or a
   // DownloadInterruptReason on failure. Upon success, the file at |full_path()|
   // is assumed to be owned by the BaseFile. It will be deleted when the
   // BaseFile object is destroyed unless Detach() is called before destroying
   // the BaseFile instance.
   //
   // |full_path|: Full path to the download file. Can be empty, in which case
@@ skipping 198 matching lines @@
   // won't delete it on destruction.
   bool detached_ = false;
 
   // Whether the file is sparse.
   // TODO(qinmin): pass the slice information to this class so that we can
   // verify that writes are not overlapping.
   bool is_sparse_file_ = false;
 
   net::NetLogWithSource net_log_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(BaseFile);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_BASE_FILE_H_