Remove support for the keygen tag

chrome/renderer/content_settings_observer.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.
 
 #ifndef CHROME_RENDERER_CONTENT_SETTINGS_OBSERVER_H_
 #define CHROME_RENDERER_CONTENT_SETTINGS_OBSERVER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 62 matching lines @@
   bool allowPlugins(bool enabled_per_settings) override;
   bool allowScript(bool enabled_per_settings) override;
   bool allowScriptFromSource(bool enabled_per_settings,
                              const blink::WebURL& script_url) override;
   bool allowStorage(bool local) override;
   bool allowReadFromClipboard(bool default_value) override;
   bool allowWriteToClipboard(bool default_value) override;
   bool allowMutationEvents(bool default_value) override;
   void didNotAllowPlugins() override;
   void didNotAllowScript() override;
-  void didUseKeygen() override;
   bool allowRunningInsecureContent(bool allowed_per_settings,
                                    const blink::WebSecurityOrigin& context,
                                    const blink::WebURL& url) override;
   bool allowAutoplay(bool default_value) override;
   void passiveInsecureContentFound(const blink::WebURL&) override;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(ContentSettingsObserverTest, WhitelistedSchemes);
   FRIEND_TEST_ALL_PREFIXES(ChromeRenderViewTest,
                            ContentSettingsInterstitialPages);
@@ skipping 65 matching lines @@
       std::unordered_map<int, blink::WebContentSettingCallbacks>;
   PermissionRequestMap permission_requests_;
 
   // If true, IsWhitelistedForContentSettings will always return true.
   const bool should_whitelist_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentSettingsObserver);
 };
 
 #endif  // CHROME_RENDERER_CONTENT_SETTINGS_OBSERVER_H_