Remove support for the keygen tag

chrome/renderer/content_settings_observer.cc

Index: chrome/renderer/content_settings_observer.cc
diff --git a/chrome/renderer/content_settings_observer.cc b/chrome/renderer/content_settings_observer.cc
index e9a614cd39d0c5f2f2a567fc80cfc5c862bc5eb8..afbaab30f3b3dbf5533629e2e07589799e96cc44 100644
--- a/chrome/renderer/content_settings_observer.cc
+++ b/chrome/renderer/content_settings_observer.cc
@@ -415,12 +415,6 @@ void ContentSettingsObserver::passiveInsecureContentFound(
   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);
 }