Oilpan: Prepare to move RenderObject and RenderObjectChildList to Oilpan heap.

Source/core/dom/FullscreenElementStack.cpp

Index: Source/core/dom/FullscreenElementStack.cpp
diff --git a/Source/core/dom/FullscreenElementStack.cpp b/Source/core/dom/FullscreenElementStack.cpp
index 7bd45e1839ba16a358958da4ac21aa3e256a1b8b..9797fa4ff3a6573012ad2d9c7bf493a282663ace 100644
--- a/Source/core/dom/FullscreenElementStack.cpp
+++ b/Source/core/dom/FullscreenElementStack.cpp
@@ -123,7 +123,7 @@ bool FullscreenElementStack::isFullScreen(Document& document)
 FullscreenElementStack::FullscreenElementStack(Document& document)
     : DocumentLifecycleObserver(&document)
     , m_areKeysEnabledInFullScreen(false)
-    , m_fullScreenRenderer(0)
+    , m_fullScreenRenderer(nullptr)
     , m_eventQueueTimer(this, &FullscreenElementStack::eventQueueTimerFired)
 {
     document.setHasFullscreenElementStack();
@@ -501,7 +501,7 @@ void FullscreenElementStack::setFullScreenRenderer(RenderFullScreen* renderer)
 
 void FullscreenElementStack::fullScreenRendererDestroyed()
 {
-    m_fullScreenRenderer = 0;
+    m_fullScreenRenderer = nullptr;
 }
 
 void FullscreenElementStack::enqueueChangeEvent(Document& document)
@@ -592,6 +592,7 @@ void FullscreenElementStack::trace(Visitor* visitor)
 {
     visitor->trace(m_fullScreenElement);
     visitor->trace(m_fullScreenElementStack);
+    visitor->trace(m_fullScreenRenderer);
     visitor->trace(m_eventQueue);
     DocumentSupplement::trace(visitor);
 }