[Downloads] Some UMA for downloads resumption.

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_
 
 #include <string>
@@ skipping 50 matching lines @@
   // This can happen when saving web pages as complete packages. It happens
   // when we get messages to append data to files that have already finished and
   // been detached, but haven't yet been removed from the list of files in
   // progress.
   APPEND_TO_DETACHED_FILE_COUNT,
 
   // Counts the number of instances where the downloaded file is missing after a
   // successful invocation of ScanAndSaveDownloadedFile().
   FILE_MISSING_AFTER_SUCCESSFUL_SCAN_COUNT,
 
+  // Count of downloads that supplies a strong ETag and has a 'Accept-Ranges:
+  // bytes' header. These downloads are candidates for partial resumption.
+  STRONG_ETAG_AND_ACCEPTS_RANGES,
+
+  // Count of downloads that didn't have a valid WebContents at the time it was
+  // interrupted.
+  INTERRUPTED_WITHOUT_WEBCONTENTS,
+
   DOWNLOAD_COUNT_TYPES_LAST_ENTRY
 };
 
 enum DownloadSource {
   // The download was initiated when the SavePackage system rejected
   // a Save Page As ... by returning false from
   // SavePackage::IsSaveableContents().
   INITIATED_BY_SAVE_PACKAGE_ON_NON_HTML = 0,
 
   // The download was initiated by a drag and drop from a drag-and-drop
   // enabled web application.
   INITIATED_BY_DRAG_N_DROP,
 
   // The download was initiated by explicit RPC from the renderer process
   // (e.g. by Alt-click) through the IPC ViewHostMsg_DownloadUrl.
   INITIATED_BY_RENDERER,
 
+  // Fomerly INITIATED_BY_PEPPER_SAVE.
+  DOWNLOAD_SOURCE_UNUSED_3,
+
+  // A request that was initiated as a result of resuming an interrupted
+  // download.
+  INITIATED_BY_RESUMPTION,
+
   DOWNLOAD_SOURCE_LAST_ENTRY
 };
 
 enum DownloadDiscardReason {
   // The download is being discarded due to a user action.
   DOWNLOAD_DISCARD_DUE_TO_USER_ACTION,
 
   // The download is being discarded due to the browser being shut down.
   DOWNLOAD_DISCARD_DUE_TO_SHUTDOWN
 };
@@ skipping 36 matching lines @@
 void RecordFileThreadReceiveBuffers(size_t num_buffers);
 
 // Record the bandwidth seen in DownloadResourceHandler
 // |actual_bandwidth| and |potential_bandwidth| are in bytes/second.
 void RecordBandwidth(double actual_bandwidth, double potential_bandwidth);
 
 // 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 whether or not the server accepts ranges, and the download size.
-void RecordAcceptsRanges(const std::string& accepts_ranges, int64 download_len);
+// Record whether or not the server accepts ranges, and the download size. Also
+// counts if a strong ETag is supplied. The combination of range request support
+// and ETag indicates downloads that are candidates for partial resumption.
+void RecordAcceptsRanges(const std::string& accepts_ranges, int64 download_len,
+                         const std::string& etag);
 
 // 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);
 
@@ skipping 25 matching lines @@
   SAVE_PACKAGE_WRITE_TO_FAILED,
 
   SAVE_PACKAGE_LAST_ENTRY
 };
 
 void RecordSavePackageEvent(SavePackageEvent event);
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_STATS_H_