Delete TLS version fallback code in net/http.

net/log/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 514 matching lines @@
 // An SSL error occurred while trying to do the indicated activity.
 // The following parameters are attached to the event:
 //   {
 //     "net_error": <Integer code for the specific error type>,
 //     "ssl_lib_error": <SSL library's integer code for the specific error type>
 //   }
 EVENT_TYPE(SSL_HANDSHAKE_ERROR)
 EVENT_TYPE(SSL_READ_ERROR)
 EVENT_TYPE(SSL_WRITE_ERROR)
 
-// An SSL connection needs to be retried with a lower protocol version because
-// the server may be intolerant of the protocol version we offered.
-// The following parameters are attached to the event:
-//   {
-//     "host_and_port": <String encoding the host and port>,
-//     "net_error": <Net integer error code>,
-//     "version_before": <SSL version before the fallback>,
-//     "version_after": <SSL version after the fallback>,
-//   }
-EVENT_TYPE(SSL_VERSION_FALLBACK)
-

[Ryan Sleevi, 2016/06/24 18:51:26]

Do we need to preserve these IDs in any meaningful way? Just confirming "no" -
there's no need to keep legacy events

[eroman, 2016/06/24 18:56:07]

No, there is no need to preserve IDs. Legacy log files will still load
correctly.

The log file format includes the symbolic names.
Both for these event types, but also for things like net error codes.

LGTM

 // An SSL connection needs to be retried with more cipher suites because the
 // server may require a deprecated cipher suite. The following parameters are
 // attached to the event:
 //   {
 //     "host_and_port": <String encoding the host and port>,
 //     "net_error": <Net integer error code>,
 //   }
 EVENT_TYPE(SSL_CIPHER_FALLBACK)
 
 // We found that our prediction of the server's certificates was correct and
@@ skipping 2422 matching lines @@
 // The start/end of some portion of the SAFE_BROWSING_CHECKING_URL during which
 // the request is delayed due to that check.
 //
 // The BEGIN phase contains the following parameters:
 //  {
 //    "url": <The URL being checked>,
 //    "defer_reason" : < "at_start", "at_response", "redirect",
 //                       "resumed_redirect", "unchecked_redirect">
 //  }
 EVENT_TYPE(SAFE_BROWSING_DEFERRED)