Simulate click through gamepad BUTTON_A

third_party/WebKit/Source/core/html/forms/BaseCheckableInputType.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 41 matching lines @@
 }
 
 void BaseCheckableInputType::appendToFormData(FormData& formData) const
 {
     if (element().checked())
         formData.append(element().name(), element().value());
 }
 
 void BaseCheckableInputType::handleKeydownEvent(KeyboardEvent* event)
 {
     const String& key = event->keyIdentifier();

[dtapuska, 2016/02/09 14:29:03]

As per the similar comment before; keyIdentifier will eventually be removed. 
So using domCode() or keyCode() is preferred for now.
Currently we don't have domKey() working everywhere so ideally you'd use that.
Personally I'd use the keyCode() == ' ' || keyCode() == '\r'

-    if (key == "U+0020") {
+    if (key == "U+0020" || key == "Enter") {
         element().setActive(true);
         // No setDefaultHandled(), because IE dispatches a keypress in this case
         // and the caller will only dispatch a keypress if we don't call setDefaultHandled().
     }
 }
 
 void BaseCheckableInputType::handleKeypressEvent(KeyboardEvent* event)
 {
     if (event->charCode() == ' ') {
         // Prevent scrolling down the page.
@@ skipping 39 matching lines @@
 {
     return true;
 }
 
 bool BaseCheckableInputType::shouldDispatchFormControlChangeEvent(String& oldValue, String& newValue)
 {
     return oldValue != newValue;
 }
 
 } // namespace blink