Add new UMA stats to get a handle on Downloads UI Usage

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
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
 
 namespace base {
+class Time;
 class TimeTicks;
 }
 
 namespace download_stats {
 
 // We keep a count of how often various events occur in the
 // histogram "Download.Counts".
 enum DownloadCountTypes {
   // The download was initiated by navigating to a URL (e.g. by user
   // click).
@@ skipping 54 matching lines @@
 
 // Records the mime type of the download.
 void RecordDownloadMimeType(const std::string& mime_type);
 
 // Record WRITE_SIZE_COUNT and data_len.
 void RecordDownloadWriteSize(size_t data_len);
 
 // Record WRITE_LOOP_COUNT and number of loops.
 void RecordDownloadWriteLoopCount(int count);
 
+// Record the time of both the first open and all subsequent opens since the
+// download completed.
+void RecordOpen(const base::Time& end, bool first);
+
+// Record the number of items loaded from the history db.
+void RecordHistorySize(int size);
+
+// Record the number of items that are in the history at the time that a
+// new download begins.
+void RecordHistorySize2(int size);
+
+// Record the number of items showing in the shelf when it closes.
+void RecordShelfSize(int size);
+
+// Record the number of pending items showing in the shelf when it closes.
+void RecordShelfPendingSize(int size);
+
+// 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);
+
 }  // namespace download_stats
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_