stale-while-revalidate experimental implementation.

net/base/net_log_event_type_list.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.
 
 // NOTE: No header guards are used, since this file is intended to be expanded
 // directly into net_log.h. DO NOT include this file anywhere else.
 
 // In the event of a failure, a many end events will have a |net_error|
 // parameter with the integer error code associated with the failure.  Most
 // of these parameters are not individually documented.
@@ skipping 817 matching lines @@
 
 // Measures the time while reading/writing a disk cache entry's response headers
 // or metadata.
 EVENT_TYPE(HTTP_CACHE_READ_INFO)
 EVENT_TYPE(HTTP_CACHE_WRITE_INFO)
 
 // Measures the time while reading/writing a disk cache entry's body.
 EVENT_TYPE(HTTP_CACHE_READ_DATA)
 EVENT_TYPE(HTTP_CACHE_WRITE_DATA)
 
+// Identifies the NetLog::Source() for the asynchronous HttpCache::Transaction
+// that will revalidate this entry.
+// The event parameters are:
+//   {
+//      "source_dependency": <Source identifier for the async Transaction>
+//   }
+EVENT_TYPE(HTTP_CACHE_VALIDATE_RESOURCE_ASYNC)
+
+// The start/end of performing an async revalidation.
+// For the BEGIN phase, the event parameters are:
+//   {
+//      "source_dependency": <Source identifier for the Request>
+//      "url": <String of URL being loaded>,
+//      "method": <Method of request>
+//   }
+//
+// For the END phase, if there was an error, the following parameters are
+// attached:
+//   {
+//      "net_error": <Net error code of the failure>,
+//   }
+EVENT_TYPE(ASYNC_REVALIDATION)
+
 // ------------------------------------------------------------------------
 // Disk Cache / Memory Cache
 // ------------------------------------------------------------------------
 
 // The creation/destruction of a disk_cache::EntryImpl object.  The "creation"
 // is considered to be the point at which an Entry is first considered to be
 // good and associated with a key.  Note that disk and memory cache entries
 // share event types.
 //
 // For the BEGIN phase, the following parameters are attached:
@@ skipping 1538 matching lines @@
 // entry.  It contains no parameters.
 EVENT_TYPE(SIMPLE_CACHE_ENTRY_CLOSE_BEGIN)
 
 // This event is created when the Simple Cache finishes a CloseEntry call.  It
 // contains no parameters.
 EVENT_TYPE(SIMPLE_CACHE_ENTRY_CLOSE_END)
 
 // This event is created (in a source of the same name) when the internal DNS
 // resolver creates a UDP socket to check for global IPv6 connectivity.
 EVENT_TYPE(IPV6_REACHABILITY_CHECK)