Deprecate FLAGS_quic_disable_pre_30. Remove QUIC versions [25-29].

net/tools/quic/quic_dispatcher.cc

 // 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.
 
 #include "net/tools/quic/quic_dispatcher.h"
 
 #include <utility>
 
 #include "base/debug/stack_trace.h"
 #include "base/logging.h"
@@ skipping 184 matching lines @@
       crypto_config_(crypto_config),
       compressed_certs_cache_(
           QuicCompressedCertsCache::kQuicCompressedCertsCacheSize),
       helper_(std::move(helper)),
       session_helper_(std::move(session_helper)),
       alarm_factory_(std::move(alarm_factory)),
       delete_sessions_alarm_(
           alarm_factory_->CreateAlarm(new DeleteSessionsAlarm(this))),
       buffered_packets_(this, helper_->GetClock(), alarm_factory_.get()),
       supported_versions_(supported_versions),
-      disable_quic_pre_30_(FLAGS_quic_disable_pre_30),
       allowed_supported_versions_(supported_versions),
       current_packet_(nullptr),
       framer_(supported_versions,
               /*unused*/ QuicTime::Zero(),
               Perspective::IS_SERVER),
       last_error_(QUIC_NO_ERROR) {
   framer_.set_visitor(this);
 }
 
 QuicDispatcher::~QuicDispatcher() {
@@ skipping 518 matching lines @@
       return kFateTimeWait;
     }
   }
 
   QUIC_BUG << "Rejector has unknown invalid state.";
   return kFateDrop;
 }
 
 const QuicVersionVector& QuicDispatcher::GetSupportedVersions() {
   // Filter (or un-filter) the list of supported versions based on the flag.
-  if (disable_quic_pre_30_ != FLAGS_quic_disable_pre_30) {
+  if (false) {
     DCHECK_EQ(supported_versions_.capacity(),
               allowed_supported_versions_.capacity());
-    disable_quic_pre_30_ = FLAGS_quic_disable_pre_30;
     supported_versions_ = FilterSupportedVersions(allowed_supported_versions_);
   }

[Zhongyi Shi, 2016/07/25 22:52:49]

nit: though this looks consistent with the internal CL. But out of curiosity,
why do we have this chunk of code left here?

[Ryan Hamilton, 2016/07/25 23:07:34]

'cause this code is going to come back RSN with v35 and v36. (Fan is working on
this). But yeah. This is warty.

   return supported_versions_;
 }
 
 }  // namespace net