Introduce ParallelDownloadJob.

content/browser/download/download_item_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_ITEM_IMPL_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 10 matching lines @@
 #include "content/browser/download/download_request_handle.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 #include "content/public/browser/download_item.h"
 #include "net/log/net_log_with_source.h"
 #include "url/gurl.h"
 
 namespace content {
 class DownloadFile;
 class DownloadItemImplDelegate;
+class DownloadJob;
 
 // See download_item.h for usage.
 class CONTENT_EXPORT DownloadItemImpl
     : public DownloadItem,
       public DownloadDestinationObserver {
  public:
   enum ResumeMode {
     RESUME_MODE_INVALID = 0,
     RESUME_MODE_IMMEDIATE_CONTINUE,
     RESUME_MODE_IMMEDIATE_RESTART,
@@ skipping 180 matching lines @@
   void DestinationUpdate(int64_t bytes_so_far, int64_t bytes_per_sec) override;
   void DestinationError(
       DownloadInterruptReason reason,
       int64_t bytes_so_far,
       std::unique_ptr<crypto::SecureHash> hash_state) override;
   void DestinationCompleted(
       int64_t total_bytes,
       std::unique_ptr<crypto::SecureHash> hash_state) override;
 
  private:
+  friend class DownloadJob;
+
   // Fine grained states of a download.
   //
   // New downloads can be created in the following states:
   //
   //     INITIAL_INTERNAL:        All active new downloads.
   //
   //     COMPLETE_INTERNAL:       Downloads restored from persisted state.
   //     CANCELLED_INTERNAL:      - do -
   //     INTERRUPTED_INTERNAL:    - do -
   //
@@ skipping 143 matching lines @@
   // These are listed in approximately chronological order.  There are also
   // public methods involved in normal download progression; see
   // the implementation ordering in download_item_impl.cc.
 
   // Construction common to all constructors. |active| should be true for new
   // downloads and false for downloads from the history.
   // |download_type| indicates to the net log system what kind of download
   // this is.
   void Init(bool active, DownloadType download_type);
 
+  // Start a series of events that result in the file being downloaded.
+  void StartDownloadProgress();

[qinmin, 2017/02/23 07:26:57]

nit: StartDownloadProgress() doesn't sounds like a commonly used phrase. Either
StartDownload(), or StartDownloadProcess() or StartFileDownload() sounds much
better.

[xingliu, 2017/02/24 23:43:13]

Done, changed to StartDownload.

+
   // Callback from file thread when we initialize the DownloadFile.
   void OnDownloadFileInitialized(DownloadInterruptReason result);
 
   // Called to determine the target path. Will cause OnDownloadTargetDetermined
   // to be called when the target information is available.
   void DetermineDownloadTarget();
 
   // Called when the target path has been determined. |target_path| is the
   // suggested target path. |disposition| indicates how the target path should
   // be used (see TargetDisposition). |danger_type| is the danger level of
@@ skipping 90 matching lines @@
   static const char* DebugResumeModeString(ResumeMode mode);
   static bool IsValidSavePackageStateTransition(DownloadInternalState from,
                                                 DownloadInternalState to);
   static bool IsValidStateTransition(DownloadInternalState from,
                                      DownloadInternalState to);
 
   // Will be false for save package downloads retrieved from the history.
   // TODO(rdsmith): Replace with a generalized enum for "download source".
   const bool is_save_package_download_ = false;
 
-  // The handle to the request information.  Used for operations outside the
-  // download system.
-  std::unique_ptr<DownloadRequestHandleInterface> request_handle_;
-
   std::string guid_;
 
   uint32_t download_id_ = kInvalidId;
 
   // Display name for the download. If this is empty, then the display name is
   // considered to be |target_path_.BaseName()|.
   base::FilePath display_name_;
 
   // Target path of an in-progress download. We may be downloading to a
   // temporary or intermediate file (specified by |current_path_|.  Once the
@@ skipping 69 matching lines @@
 
   // Time the download was started.
   base::Time start_time_;
 
   // Time the download completed.
   base::Time end_time_;
 
   // Our delegate.
   DownloadItemImplDelegate* delegate_ = nullptr;
 
-  // In progress downloads may be paused by the user, we note it here.
-  bool is_paused_ = false;
-
   // A flag for indicating if the download should be opened at completion.
   bool open_when_complete_ = false;
 
   // A flag for indicating if the downloaded file is externally removed.
   bool file_externally_removed_ = false;
 
   // True if the download was auto-opened. We set this rather than using
   // an observer as it's frequently possible for the download to be auto opened
   // before the observer is added.
   bool auto_opened_ = false;
@@ skipping 60 matching lines @@
 
   // Contents of the Last-Modified header for the most recent server response.
   std::string last_modified_time_;
 
   // Server's ETAG for the file.
   std::string etag_;
 
   // Net log to use for this download.
   const net::NetLogWithSource net_log_;
 
+  std::unique_ptr<DownloadJob> job_;
+
   base::WeakPtrFactory<DownloadItemImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadItemImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_ITEM_IMPL_H_