Remove GamePad runtime flag(status=stable)

Source/modules/gamepad/NavigatorGamepad.cpp

 /*
  * Copyright (C) 2011, Google 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:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 206 matching lines @@
     return false;
 }
 
 static bool isGamepadEvent(const AtomicString& eventType)
 {
     return eventType == EventTypeNames::gamepadconnected || eventType == EventTypeNames::gamepaddisconnected;
 }
 
 void NavigatorGamepad::didAddEventListener(LocalDOMWindow*, const AtomicString& eventType)
 {
-    if (RuntimeEnabledFeatures::gamepadEnabled() && isGamepadEvent(eventType)) {
+    if (isGamepadEvent(eventType)) {
         if (page() && page()->visibilityState() == PageVisibilityStateVisible)
             startUpdating();
         m_hasEventListener = true;
     }
 }
 
 void NavigatorGamepad::didRemoveEventListener(LocalDOMWindow* window, const AtomicString& eventType)
 {
     if (isGamepadEvent(eventType)
         && !window->hasEventListeners(EventTypeNames::gamepadconnected)
@@ skipping 46 matching lines @@
         if (connectedGamepadChanged || (!oldWasConnected && newIsConnected)) {
             m_pendingEvents.append(newGamepad);
         }
     }
 
     if (!m_pendingEvents.isEmpty())
         m_dispatchOneEventRunner.runAsync();
 }
 
 } // namespace blink