Remove support for the keygen tag

chrome/renderer/content_settings_observer.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 "chrome/renderer/content_settings_observer.h"
 
 #include "chrome/common/render_messages.h"
 #include "chrome/common/ssl_insecure_content.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/renderer/document_state.h"
@@ skipping 397 matching lines @@
              url::Origin(frame->document().getSecurityOrigin()).GetURL()) ==
          CONTENT_SETTING_ALLOW;
 }
 
 void ContentSettingsObserver::passiveInsecureContentFound(
     const blink::WebURL& resource_url) {
   ReportInsecureContent(SslInsecureContentType::DISPLAY);
   FilteredReportInsecureContentDisplayed(GURL(resource_url));
 }
 
-void ContentSettingsObserver::didUseKeygen() {
-  WebFrame* frame = render_frame()->GetWebFrame();
-  Send(new ChromeViewHostMsg_DidUseKeygen(
-      routing_id(), url::Origin(frame->getSecurityOrigin()).GetURL()));
-}
-
 void ContentSettingsObserver::didNotAllowPlugins() {
   DidBlockContentType(CONTENT_SETTINGS_TYPE_PLUGINS);
 }
 
 void ContentSettingsObserver::didNotAllowScript() {
   DidBlockContentType(CONTENT_SETTINGS_TYPE_JAVASCRIPT);
 }
 
 void ContentSettingsObserver::OnLoadBlockedPlugins(
     const std::string& identifier) {
@@ skipping 101 matching lines @@
 
   // If the scheme is file:, an empty file name indicates a directory listing,
   // which requires JavaScript to function properly.
   if (base::EqualsASCII(protocol, url::kFileScheme)) {
     return document_url.SchemeIs(url::kFileScheme) &&
            document_url.ExtractFileName().empty();
   }
 
   return false;
 }