Use ByteStream in downloads system to decouple source and sink.

content/browser/download/download_stats.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.
 //
 // Holds helpers for gathering UMA stats about downloads.
 
 #ifndef CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_
 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_
 #pragma once
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 
 namespace base {
 class Time;
+class TimeDelta;
 class TimeTicks;
 }
 
 namespace download_stats {
 
 // We keep a count of how often various events occur in the
 // histogram "Download.Counts".
 enum DownloadCountTypes {
   // Stale enum values left around so that values passed to UMA don't
   // change.
@@ skipping 101 matching lines @@
 
 // Record whether or not the server accepts ranges, and the download size.
 void RecordAcceptsRanges(const std::string& accepts_ranges, int64 download_len);
 
 // Record the number of downloads removed by ClearAll.
 void RecordClearAllSize(int size);
 
 // Record the number of completed unopened downloads when a download is opened.
 void RecordOpensOutstanding(int size);
 
+// Record how long we block the file thread at a time.
+void RecordContiguousWriteTime(base::TimeDelta time_blocked);
+
+// Record overall bandwidth stats at the network end.
+void RecordNetworkBandwidth(size_t length,
+                            base::TimeDelta elapsed_time,
+                            base::TimeDelta paused_time);
+
+// Record overall bandwidth stats at the file end.
+void RecordFileBandwidth(size_t length,
+                         base::TimeDelta disk_write_time,
+                         base::TimeDelta elapsed_time);
+
 enum SavePackageEvent {
   // The user has started to save a page as a package.
   SAVE_PACKAGE_STARTED,
 
   // The save package operation was cancelled.
   SAVE_PACKAGE_CANCELLED,
 
   // The save package operation finished without being cancelled.
   SAVE_PACKAGE_FINISHED,
 
   // The save package tried to write to an already completed file.
   SAVE_PACKAGE_WRITE_TO_COMPLETED,
 
   // The save package tried to write to an already failed file.
   SAVE_PACKAGE_WRITE_TO_FAILED,
 
   SAVE_PACKAGE_LAST_ENTRY
 };
 
 void RecordSavePackageEvent(SavePackageEvent event);
 
 }  // namespace download_stats
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_