Implement chrome.experimental.downloads.onChanged

content/browser/download/download_stats.h

 // Copyright (c) 2011 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
 
@@ skipping 111 matching lines @@
 // in the shelf when it closes.  Set |autoclose| to true when the shelf is
 // closing itself, false when the user explicitly closed it.
 CONTENT_EXPORT void RecordShelfClose(int size, int in_progress, bool autoclose);
 
 // 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 many DownloadItem::Observer::OnDownloadUpdated are irrelevant to
+// the extensions api compared to the number that are relevant.
+CONTENT_EXPORT void RecordOnChanged(int percent);
+
 }  // namespace download_stats
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_