Oilpan: reliably track listening PlatformEventControllers.

Source/modules/battery/BatteryManager.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "modules/battery/BatteryManager.h"
 
 #include "core/dom/Document.h"
 #include "core/events/Event.h"
 #include "modules/battery/BatteryDispatcher.h"
@@ skipping 23 matching lines @@
 }
 
 ScriptPromise BatteryManager::startRequest(ScriptState* scriptState)
 {
     if (m_state == Pending)
         return m_resolver->promise();
 
     m_resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = m_resolver->promise();
 
-    if (m_state == Resolved) {
+    ASSERT(executionContext());
+    // If the context is in a stopped state already, do not start updating.
+    if (m_state == Resolved || executionContext()->activeDOMObjectsAreStopped()) {
         // FIXME: Consider returning the same promise in this case. See crbug.com/385025.
+        m_state = Resolved;
         m_resolver->resolve(this);
         m_resolver = nullptr;
     } else if (m_state == NotStarted) {
         m_state = Pending;
         m_hasEventListener = true;
         startUpdating();
     }
 
     return promise;
 }
@@ skipping 28 matching lines @@
 
     if (m_state == Pending) {
         ASSERT(m_resolver);
         m_state = Resolved;
         m_resolver->resolve(this);
         m_resolver = nullptr;
         return;
     }
 
     Document* document = toDocument(executionContext());
+    ASSERT(document);
     if (document->activeDOMObjectsAreSuspended() || document->activeDOMObjectsAreStopped())
         return;
 
     ASSERT(oldStatus);
 
     if (m_batteryStatus->charging() != oldStatus->charging())
         dispatchEvent(Event::create(EventTypeNames::chargingchange));
     if (m_batteryStatus->chargingTime() != oldStatus->chargingTime())
         dispatchEvent(Event::create(EventTypeNames::chargingtimechange));
     if (m_batteryStatus->dischargingTime() != oldStatus->dischargingTime())
@@ skipping 39 matching lines @@
 bool BatteryManager::hasPendingActivity() const
 {
     // Prevent V8 from garbage collecting the wrapper object if there are
     // event listeners attached to it.
     return m_state == Resolved && hasEventListeners();
 }
 
 void BatteryManager::trace(Visitor* visitor)
 {
     visitor->trace(m_batteryStatus);
+    PlatformEventController::trace(visitor);
     EventTargetWithInlineData::trace(visitor);
 }
 
 } // namespace blink