Remove support for the keygen tag

content/browser/renderer_host/render_message_filter.h

Index: content/browser/renderer_host/render_message_filter.h
diff --git a/content/browser/renderer_host/render_message_filter.h b/content/browser/renderer_host/render_message_filter.h
index 6c632f577f5fd6ded733f841f28d442ff2bcf92d..7231427ecd1ec37c4cd92fe92b7a4f9869769815 100644
--- a/content/browser/renderer_host/render_message_filter.h
+++ b/content/browser/renderer_host/render_message_filter.h
@@ -63,7 +63,6 @@ struct MediaLogEvent;
 
 namespace net {
 class IOBuffer;
-class KeygenHandler;
 class URLRequestContextGetter;
 }
 
@@ -193,17 +192,6 @@ class CONTENT_EXPORT RenderMessageFilter
       int buf_len,
       std::unique_ptr<CacheStorageCacheHandle> cache_handle,
       CacheStorageError error);
-  void OnKeygen(uint32_t key_size_index,
-                const std::string& challenge_string,
-                const GURL& url,
-                const GURL& top_origin,
-                IPC::Message* reply_msg);
-  void PostKeygenToWorkerThread(
-      IPC::Message* reply_msg,
-      std::unique_ptr<net::KeygenHandler> keygen_handler);
-  void OnKeygenOnWorkerThread(
-      std::unique_ptr<net::KeygenHandler> keygen_handler,
-      IPC::Message* reply_msg);
   void OnMediaLogEvents(const std::vector<media::MediaLogEvent>&);
 
   bool CheckBenchmarkingEnabled() const;