[ResourceScheduler] Make throttling H2+QUIC default disabled

content/browser/loader/resource_scheduler.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 "content/browser/loader/resource_scheduler.h"
 
 #include <stdint.h>
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 19 matching lines @@
 
 namespace content {
 
 namespace {
 
 // When kPrioritySupportedRequestsDelayable is enabled, requests for
 // H2/QUIC/SPDY resources can be delayed by the ResourceScheduler just as
 // HTTP/1.1 resources are. Disabling this appears to have negative performance
 // impact, see https://crbug.com/655585.
 const base::Feature kPrioritySupportedRequestsDelayable{
-    "PrioritySupportedRequestsDelayable", base::FEATURE_ENABLED_BY_DEFAULT};
+    "PrioritySupportedRequestsDelayable", base::FEATURE_DISABLED_BY_DEFAULT};
 
 enum StartMode {
   START_SYNC,
   START_ASYNC
 };
 
 // Flags identifying various attributes of the request that are used
 // when making scheduling decisions.
 using RequestAttributes = uint8_t;
 const RequestAttributes kAttributeNone = 0x00;
@@ skipping 863 matching lines @@
   client->ReprioritizeRequest(scheduled_resource_request, old_priority_params,
                               new_priority_params);
 }
 
 ResourceScheduler::ClientId ResourceScheduler::MakeClientId(
     int child_id, int route_id) {
   return (static_cast<ResourceScheduler::ClientId>(child_id) << 32) | route_id;
 }
 
 }  // namespace content