Remove support for the keygen tag

chrome/common/render_messages.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.
 
 // Multiply-included file, no traditional include guard.
 #include <stdint.h>
 #include <string>
 #include <vector>
 
 #include "base/files/file_path.h"
@@ skipping 366 matching lines @@
                             bool /* allowed */)
 
 // Sent by the renderer process to check whether access to FileSystem is
 // granted by content settings.
 IPC_SYNC_MESSAGE_CONTROL3_1(ChromeViewHostMsg_RequestFileSystemAccessSync,
                             int /* render_frame_id */,
                             GURL /* origin_url */,
                             GURL /* top origin url */,
                             bool /* allowed */)
 
-// Sent by the renderer process when a keygen element is rendered onto the
-// current page.
-IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_DidUseKeygen,
-                    GURL /* origin_url */)
-
 // Sent by the renderer process to check whether access to FileSystem is
 // granted by content settings.
 IPC_MESSAGE_CONTROL4(ChromeViewHostMsg_RequestFileSystemAccessAsync,
                     int /* render_frame_id */,
                     int /* request_id */,
                     GURL /* origin_url */,
                     GURL /* top origin url */)
 
 // Sent by the renderer process to check whether access to Indexed DBis
 // granted by content settings.
@@ skipping 186 matching lines @@
 // process so that they can be assigned to an Instant renderer.
 IPC_MESSAGE_CONTROL2(ChromeViewMsg_SetSearchURLs,
                      std::vector<GURL> /* search_urls */,
                      GURL /* new_tab_page_url */)
 
 #if BUILDFLAG(ENABLE_PLUGINS)
 // Sent by the renderer to check if crash reporting is enabled.
 IPC_SYNC_MESSAGE_CONTROL0_1(ChromeViewHostMsg_IsCrashReportingEnabled,
                             bool /* enabled */)
 #endif