[Downloads] Factor out request handling logic between DRH and UD.

content/browser/download/download_resource_handler.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_RESOURCE_HANDLER_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_RESOURCE_HANDLER_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
+#include "content/browser/download/download_request_core.h"
 #include "content/browser/loader/resource_handler.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 #include "content/public/browser/download_manager.h"
 #include "content/public/browser/download_save_info.h"
 #include "content/public/browser/download_url_parameters.h"
 
 namespace net {
 class URLRequest;
 }  // namespace net
 
 namespace content {
 class ByteStreamReader;
 class ByteStreamWriter;
 class DownloadRequestHandle;
 class PowerSaveBlocker;
 struct DownloadCreateInfo;
 
 // Forwards data to the download thread.
 class CONTENT_EXPORT DownloadResourceHandler
     : public ResourceHandler,
       public base::SupportsWeakPtr<DownloadResourceHandler> {
  public:
   struct DownloadTabInfo;
 
-  // Size of the buffer used between the DownloadResourceHandler and the
-  // downstream receiver of its output.
-  static const int kDownloadByteStreamSize;
-
   // started_cb will be called exactly once on the UI thread.
   // |id| should be invalid if the id should be automatically assigned.
   DownloadResourceHandler(
       uint32 id,
       net::URLRequest* request,
       const DownloadUrlParameters::OnStartedCallback& started_cb,
       scoped_ptr<DownloadSaveInfo> save_info);
 
   bool OnRequestRedirected(const net::RedirectInfo& redirect_info,
                            ResourceResponse* response,
@@ skipping 30 matching lines @@
   void CancelRequest();
 
   std::string DebugString() const;
 
  private:
   ~DownloadResourceHandler() override;
 
   // Arrange for started_cb_ to be called on the UI thread with the
   // below values, nulling out started_cb_.  Should only be called
   // on the IO thread.
-  void CallStartedCB(DownloadItem* item,
-                     DownloadInterruptReason interrupt_reason);
+  void CallStartedCB(DownloadInterruptReason interrupt_reason);
+
+  void OnCoreReadyToRead();
 
   uint32 download_id_;
+
   // This is read only on the IO thread, but may only
   // be called on the UI thread.
   DownloadUrlParameters::OnStartedCallback started_cb_;
-  scoped_ptr<DownloadSaveInfo> save_info_;
 
   // Stores information about the download that must be acquired on the UI
   // thread before StartOnUIThread is called.
   // Created on IO thread, but only accessed on UI thread. |tab_info_| holds
   // the pointer until we pass it off to StartOnUIThread or DeleteSoon.
   // Marked as a scoped_ptr<> to indicate ownership of the structure, but
   // deletion must occur on the IO thread.
   scoped_ptr<DownloadTabInfo> tab_info_;
 
-  // Data flow
-  scoped_refptr<net::IOBuffer> read_buffer_;       // From URLRequest.
-  scoped_ptr<ByteStreamWriter> stream_writer_; // To rest of system.
-
-  // Keeps the system from sleeping while this ResourceHandler is alive. If the
-  // system enters power saving mode while a request is alive, it can cause the
-  // request to fail and the associated download will be interrupted.
-  scoped_ptr<PowerSaveBlocker> power_save_blocker_;
-
-  // The following are used to collect stats.
-  base::TimeTicks download_start_time_;
-  base::TimeTicks last_read_time_;
-  base::TimeTicks last_stream_pause_time_;
-  base::TimeDelta total_pause_time_;
-  size_t last_buffer_size_;
-  int64 bytes_read_;
-
-  int pause_count_;
-  bool was_deferred_;
-
-  // For DCHECKing
-  bool on_response_started_called_;
-
-  static const int kReadBufSize = 32768;  // bytes
-  static const int kThrottleTimeMs = 200;  // milliseconds
-
+  DownloadRequestCore core_;
   DISALLOW_COPY_AND_ASSIGN(DownloadResourceHandler);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_RESOURCE_HANDLER_H_