Gracefully support Navigator Gamepad methods in a detached state.

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 66 matching lines @@
     if (!document.frame() || !document.frame()->domWindow())
         return 0;
     Navigator& navigator = document.frame()->domWindow()->navigator();
     return &from(navigator);
 }
 
 NavigatorGamepad& NavigatorGamepad::from(Navigator& navigator)
 {
     NavigatorGamepad* supplement = static_cast<NavigatorGamepad*>(WillBeHeapSupplement<Navigator>::from(navigator, supplementName()));
     if (!supplement) {
-        supplement = new NavigatorGamepad(*navigator.frame()->document());
+        supplement = new NavigatorGamepad(navigator.frame());
         provideTo(navigator, supplementName(), adoptPtrWillBeNoop(supplement));
     }
     return *supplement;
 }
 
 WebKitGamepadList* NavigatorGamepad::webkitGetGamepads(Navigator& navigator)
 {
     return NavigatorGamepad::from(navigator).webkitGamepads();
 }
 
 GamepadList* NavigatorGamepad::getGamepads(Navigator& navigator)
 {
     return NavigatorGamepad::from(navigator).gamepads();
 }
 
 WebKitGamepadList* NavigatorGamepad::webkitGamepads()
 {
-    startUpdating();
     if (!m_webkitGamepads)
         m_webkitGamepads = WebKitGamepadList::create();
-    sampleGamepads<WebKitGamepad>(m_webkitGamepads.get());
+    if (window()) {
+        startUpdating();
+        sampleGamepads<WebKitGamepad>(m_webkitGamepads.get());
+    }
     return m_webkitGamepads.get();
 }
 
 GamepadList* NavigatorGamepad::gamepads()
 {
-    startUpdating();
     if (!m_gamepads)
         m_gamepads = GamepadList::create();
-    sampleGamepads<Gamepad>(m_gamepads.get());
+    if (window()) {
+        startUpdating();
+        sampleGamepads<Gamepad>(m_gamepads.get());
+    }
     return m_gamepads.get();
 }
 
 void NavigatorGamepad::trace(Visitor* visitor)
 {
     visitor->trace(m_gamepads);
     visitor->trace(m_webkitGamepads);
 }
 
 void NavigatorGamepad::didConnectOrDisconnectGamepad(unsigned index, const blink::WebGamepad& webGamepad, bool connected)
@@ skipping 18 matching lines @@
     if (!gamepad)
         gamepad = Gamepad::create();
     sampleGamepad(index, *gamepad, webGamepad);
     m_gamepads->set(index, gamepad);
 
     const AtomicString& eventName = connected ? EventTypeNames::gamepadconnected : EventTypeNames::gamepaddisconnected;
     RefPtrWillBeRawPtr<GamepadEvent> event = GamepadEvent::create(eventName, false, true, gamepad);
     window()->dispatchEvent(event);
 }
 
-NavigatorGamepad::NavigatorGamepad(Document& document)
-    : DOMWindowProperty(document.frame())
-    , DeviceSensorEventController(document)
-    , DOMWindowLifecycleObserver(document.frame()->domWindow())
+NavigatorGamepad::NavigatorGamepad(LocalFrame* frame)
+    : DOMWindowProperty(frame)
+    , DeviceSensorEventController(frame ? frame->document() : 0)
+    , DOMWindowLifecycleObserver(frame ? frame->domWindow() : 0)
 {
 }
 
 NavigatorGamepad::~NavigatorGamepad()
 {
 }
 
 const char* NavigatorGamepad::supplementName()
 {
     return "NavigatorGamepad";
@@ skipping 34 matching lines @@
     return nullptr;
 }
 
 bool NavigatorGamepad::isNullEvent(Event*)
 {
     // This is called only when hasLastData() is true.
     ASSERT_NOT_REACHED();
     return false;
 }
 
+static bool isGamepadEvent(const AtomicString& eventType)
+{
+    return eventType == EventTypeNames::gamepadconnected || eventType == EventTypeNames::gamepaddisconnected;
+}
+
 void NavigatorGamepad::didAddEventListener(DOMWindow*, const AtomicString& eventType)
 {
-    if (RuntimeEnabledFeatures::gamepadEnabled() && (eventType == EventTypeNames::gamepadconnected || eventType == EventTypeNames::gamepaddisconnected)) {
+    if (RuntimeEnabledFeatures::gamepadEnabled() && isGamepadEvent(eventType)) {
         if (page() && page()->visibilityState() == PageVisibilityStateVisible)
             startUpdating();
         m_hasEventListener = true;
     }
 }
 
 void NavigatorGamepad::didRemoveEventListener(DOMWindow*, const AtomicString& eventType)
 {
-    if (eventType == EventTypeNames::gamepadconnected || eventType == EventTypeNames::gamepaddisconnected)
+    if (isGamepadEvent(eventType))
         m_hasEventListener = false;
 }
 
 void NavigatorGamepad::didRemoveAllEventListeners(DOMWindow*)
 {
     m_hasEventListener = false;
 }
 
 } // namespace WebCore