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

content/browser/download/download_resource_handler.h

Index: content/browser/download/download_resource_handler.h
diff --git a/content/browser/download/download_resource_handler.h b/content/browser/download/download_resource_handler.h
index 9c8f53dd8d2853d8fbc19edbc2c1a2be79e64761..a62892651af61ebb524fb531ff53e3dd0ccffcca 100644
--- a/content/browser/download/download_resource_handler.h
+++ b/content/browser/download/download_resource_handler.h
@@ -9,6 +9,7 @@
 
 #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"
@@ -33,10 +34,6 @@ class CONTENT_EXPORT 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(
@@ -87,14 +84,15 @@ class CONTENT_EXPORT DownloadResourceHandler
   // 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.
@@ -104,32 +102,7 @@ class CONTENT_EXPORT DownloadResourceHandler
   // 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);
 };