Oilpan: Remove a visitor parameter from isHeapObjectAlive

Source/core/frame/PlatformEventDispatcher.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 "core/frame/PlatformEventDispatcher.h"
 
 #include "core/frame/PlatformEventController.h"
 #include "wtf/TemporaryChange.h"
 
@@ skipping 75 matching lines @@
     // Trace the backing store, the weak(&bare) element references won't be.
     visitor->trace(m_controllers);
     visitor->template registerWeakMembers<PlatformEventDispatcher, &PlatformEventDispatcher::clearWeakMembers>(this);
 #endif
 }
 
 #if ENABLE(OILPAN)
 void PlatformEventDispatcher::clearWeakMembers(Visitor* visitor)
 {
     for (size_t i = 0; i < m_controllers.size(); ++i) {
-        if (!visitor->isHeapObjectAlive(m_controllers[i])) {
+        if (!Heap::isHeapObjectAlive(m_controllers[i])) {
             m_controllers[i] = nullptr;
             m_needsPurge = true;
         }
     }
     // Next notification will purge the empty slots.
 }
 #endif
 
 } // namespace blink