Never (re)start NavigatorGamepad platform event updating once detached.

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 79 matching lines @@
 
 GamepadList* NavigatorGamepad::getGamepads(Navigator& navigator)
 {
     return NavigatorGamepad::from(navigator).gamepads();
 }
 
 GamepadList* NavigatorGamepad::gamepads()
 {
     if (!m_gamepads)
         m_gamepads = GamepadList::create();
-    if (frame() && frame()->host()) {
-        // The frame must be attached to start updating.
-        startUpdating();
+    if (startUpdatingIfAttached())
         sampleGamepads<Gamepad>(m_gamepads.get());
-    }
     return m_gamepads.get();
 }
 
 void NavigatorGamepad::trace(Visitor* visitor)
 {
     visitor->trace(m_gamepads);
     visitor->trace(m_pendingEvents);
     WillBeHeapSupplement<Navigator>::trace(visitor);
     DOMWindowProperty::trace(visitor);
     PlatformEventController::trace(visitor);
     DOMWindowLifecycleObserver::trace(visitor);
 }
 
+bool NavigatorGamepad::startUpdatingIfAttached()
+{
+    // The frame must be attached to start updating.
+    if (frame() && frame()->host()) {
+        startUpdating();
+        return true;
+    }
+    return false;
+}
+
 void NavigatorGamepad::didUpdateData()
 {
     // We should stop listening once we detached.
     ASSERT(frame());
     ASSERT(frame()->domWindow());
 
     // We register to the dispatcher before sampling gamepads so we need to check if we actually have an event listener.
     if (!m_hasEventListener)
         return;
 
@@ skipping 79 matching lines @@
 
 static bool isGamepadEvent(const AtomicString& eventType)
 {
     return eventType == EventTypeNames::gamepadconnected || eventType == EventTypeNames::gamepaddisconnected;
 }
 
 void NavigatorGamepad::didAddEventListener(LocalDOMWindow*, const AtomicString& eventType)
 {
     if (isGamepadEvent(eventType)) {
         if (page() && page()->visibilityState() == PageVisibilityStateVisible)
-            startUpdating();
+            startUpdatingIfAttached();
         m_hasEventListener = true;
     }
 }
 
 void NavigatorGamepad::didRemoveEventListener(LocalDOMWindow* window, const AtomicString& eventType)
 {
     if (isGamepadEvent(eventType)
         && !window->hasEventListeners(EventTypeNames::gamepadconnected)
         && !window->hasEventListeners(EventTypeNames::gamepaddisconnected)) {
         didRemoveGamepadEventListeners();
@@ skipping 10 matching lines @@
     m_hasEventListener = false;
     m_dispatchOneEventRunner.stop();
     m_pendingEvents.clear();
 }
 
 void NavigatorGamepad::pageVisibilityChanged()
 {
     // Inform the embedder whether it needs to provide gamepad data for us.
     bool visible = page()->visibilityState() == PageVisibilityStateVisible;
     if (visible && (m_hasEventListener || m_gamepads))
-        startUpdating();
+        startUpdatingIfAttached();
     else
         stopUpdating();
 
     if (!visible || !m_hasEventListener)
         return;
 
     // Tell the page what has changed. m_gamepads contains the state before we became hidden.
     // We create a new snapshot and compare them.
     GamepadList* oldGamepads = m_gamepads.release();
     gamepads();
@@ skipping 13 matching lines @@
         if (connectedGamepadChanged || (!oldWasConnected && newIsConnected)) {
             m_pendingEvents.append(newGamepad);
         }
     }
 
     if (!m_pendingEvents.isEmpty())
         m_dispatchOneEventRunner.runAsync();
 }
 
 } // namespace blink