Remove support for the keygen tag

third_party/WebKit/LayoutTests/fast/forms/resources/common.js

 function $(id) {
     return document.getElementById(id);
 }
 
 function createFormControlDataSet() {
     // A list of labelable elements resides in http://www.whatwg.org/specs/web-apps/current-work/multipage/forms.html#category-label
     var formControlClassNames = [
         'HTMLButtonElement',
         'HTMLDataListElement',
         'HTMLFieldSetElement',
         'HTMLInputElement',
-        'HTMLKeygenElement',
         'HTMLLabelElement',
         'HTMLLegendElement',
         'HTMLMeterElement',
         'HTMLObjectElement',
         'HTMLOptGroupElement',
         'HTMLOptionElement',
         'HTMLOutputElement',
         'HTMLProgressElement',
         'HTMLSelectElement',
         'HTMLTextAreaElement'
@@ skipping 208 matching lines @@
         return;
     }
     for (var i = 0; i < str.length; ++i) {
         var key = str.charAt(i);
         if (key == '\n')
             key = 'Enter';
         eventSender.keyDown(key);
     }
 }