Remove support for the keygen tag

content/browser/loader/mime_sniffing_resource_handler.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/mime_sniffing_resource_handler.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 347 matching lines @@
 
 bool MimeSniffingResourceHandler::MaybeStartInterception(bool* defer) {
   if (!CanBeIntercepted())
     return true;
 
   DCHECK(!response_->head.mime_type.empty());
 
   ResourceRequestInfoImpl* info = GetRequestInfo();
   const std::string& mime_type = response_->head.mime_type;
 
-  // https://crbug.com/568184 - Temporary hack to track servers that aren't
-  // setting Content-Disposition when sending x-x509-user-cert and expecting
-  // the browser to automatically install certificates; this is being
-  // deprecated and will be removed upon full <keygen> removal.
-  if (mime_type == "application/x-x509-user-cert" && response_->head.headers) {
-    UMA_HISTOGRAM_BOOLEAN(
-        "UserCert.ContentDisposition",
-        response_->head.headers->HasHeader("Content-Disposition"));
-  }
-
   // Allow requests for object/embed tags to be intercepted as streams.
   if (info->GetResourceType() == content::RESOURCE_TYPE_OBJECT) {
     DCHECK(!info->allow_download());
 
     bool handled_by_plugin;
     if (!CheckForPluginHandler(defer, &handled_by_plugin))
       return false;
     if (handled_by_plugin || *defer)
       return true;
   }
@@ skipping 129 matching lines @@
 
 void MimeSniffingResourceHandler::OnPluginsLoaded(
     const std::vector<WebPluginInfo>& plugins) {
   // No longer blocking on the plugins being loaded.
   request()->LogUnblocked();
   if (state_ == STATE_BUFFERING)
     AdvanceState();
 }
 
 }  // namespace content