Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 023399805da574f2d514b2d8e243b7ab860decb7..5579b7a8b0210c33a9d2b5a5fd1a48217d83fe13 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -378,7 +378,9 @@ DocumentVisibilityObserver::DocumentVisibilityObserver(Document& document)
 
 DocumentVisibilityObserver::~DocumentVisibilityObserver()
 {
+#if !ENABLE(OILPAN)
     unregisterObserver();
+#endif
 }
 
 void DocumentVisibilityObserver::unregisterObserver()
@@ -522,8 +524,14 @@ Document::~Document()
     ASSERT(!renderView());
     ASSERT(m_ranges.isEmpty());
     ASSERT(!parentTreeScope());
+#if !ENABLE(OILPAN)
     ASSERT(!hasGuardRefCount());
+    // With Oilpan, either the document outlives the visibility observers
+    // or the visibility observers and the document die in the same GC round.
+    // When they die in the same GC round, the list of visibility observers
+    // will not be empty on Document destruction.

[Erik Corry, 2014/04/24 13:53:16]

Is it worth checking that they are all dead at this point?

[Mads Ager (chromium), 2014/04/24 14:12:14]

I don't think so, no.

     ASSERT(m_visibilityObservers.isEmpty());
+#endif
 
     if (m_templateDocument)
         m_templateDocument->m_templateDocumentHost = 0; // balanced in ensureTemplateDocument().
@@ -544,8 +552,10 @@ Document::~Document()
     if (this == topDocument())
         clearAXObjectCache();
 
+#if !ENABLE(OILPAN)
     if (m_styleSheetList)
         m_styleSheetList->detachFromDocument();
+#endif
 
     if (m_importsController) {
         m_importsController->wasDetachedFrom(*this);
@@ -1435,8 +1445,8 @@ void Document::didChangeVisibilityState()
     dispatchEvent(Event::create(EventTypeNames::webkitvisibilitychange));
 
     PageVisibilityState state = pageVisibilityState();
-    HashSet<DocumentVisibilityObserver*>::const_iterator observerEnd = m_visibilityObservers.end();
-    for (HashSet<DocumentVisibilityObserver*>::const_iterator it = m_visibilityObservers.begin(); it != observerEnd; ++it)
+    WillBeHeapHashSet<RawPtrWillBeWeakMember<DocumentVisibilityObserver> >::const_iterator observerEnd = m_visibilityObservers.end();

[Erik Corry, 2014/04/24 13:53:16]

I think a typedef would be good here.

[Mads Ager (chromium), 2014/04/24 14:12:14]

Done.

+    for (WillBeHeapHashSet<RawPtrWillBeWeakMember<DocumentVisibilityObserver> >::const_iterator it = m_visibilityObservers.begin(); it != observerEnd; ++it)
         (*it)->didChangeVisibilityState(state);
 }
 
@@ -4839,7 +4849,7 @@ void Document::detachRange(Range* range)
     m_ranges.remove(range);
 }
 
-void Document::getCSSCanvasContext(const String& type, const String& name, int width, int height, bool& is2d, RefPtr<CanvasRenderingContext2D>& context2d, bool& is3d, RefPtr<WebGLRenderingContext>& context3d)
+void Document::getCSSCanvasContext(const String& type, const String& name, int width, int height, bool& is2d, RefPtrWillBeRawPtr<CanvasRenderingContext2D>& context2d, bool& is3d, RefPtrWillBeRawPtr<WebGLRenderingContext>& context3d)
 {
     HTMLCanvasElement& element = getCSSCanvasElement(name);
     element.setSize(IntSize(width, height));
@@ -5042,10 +5052,32 @@ void Document::decrementLoadEventDelayCount()
     ASSERT(m_loadEventDelayCount);
     --m_loadEventDelayCount;
 
-    if (frame() && !m_loadEventDelayCount && !m_loadEventDelayTimer.isActive())
+    if (!m_loadEventDelayCount)

[Erik Corry, 2014/04/24 13:53:16]

Style guide was just revised so you can write == 0 instead of using ! here.

[Mads Ager (chromium), 2014/04/24 14:12:14]

OK, not going to bother with that right now. The rest of the code in this file
uses the other style.

+        checkLoadEventSoon();
+}
+
+void Document::checkLoadEventSoon()
+{
+    if (frame() && !m_loadEventDelayTimer.isActive())
         m_loadEventDelayTimer.startOneShot(0, FROM_HERE);
 }
 
+bool Document::isDelayingLoadEvent()
+{
+#if ENABLE(OILPAN)
+    // With Oilpan, always delay load events until after garbage collection.

[Erik Corry, 2014/04/24 13:53:16]

The "With Oilpan" part of the comment is obsolete when we remove the ifdefs, and
right now it is superfluous due to its proximity to the ifdef, so I suggest it
be removed.

[Mads Ager (chromium), 2014/04/24 14:12:14]

Yes, true. Done.

+    // This way we don't have to explicitly delay load events via
+    // incrementLoadEventDelayCount and decrementLoadEventDelayCount in
+    // Node destructors.
+    if (!m_loadEventDelayCount && ThreadState::current()->isSweepInProgress()) {
+        checkLoadEventSoon();

[Erik Corry, 2014/04/24 13:53:16]

Just because we asked whether load events are being delayed we have to check for
load events?  Seems like you should only call this if a sweep is in progress, or
perhaps we could call it once in the GC epilogue?

[Mads Ager (chromium), 2014/04/24 14:12:14]

Good point. Done. If we are sweeping, we check for load events soon if we are
not otherwise delaying load events.

+        return true;
+    }
+#endif
+    return m_loadEventDelayCount;

[Erik Corry, 2014/04/24 13:53:16]

!= 0

[Mads Ager (chromium), 2014/04/24 14:12:14]

Nah, not in this change. The rest of this code uses the old style and I'm not
going to start changing the style of one method here.

+}
+
+
 void Document::loadEventDelayTimerFired(Timer<Document>*)
 {
     if (frame())
@@ -5599,9 +5631,33 @@ void Document::invalidateNodeListCaches(const QualifiedName* attrName)
         (*it)->invalidateCacheForAttribute(attrName);
 }
 
+void Document::clearWeakMembers(Visitor* visitor)
+{
+    if (m_axObjectCache)
+        m_axObjectCache->clearWeakMembers(visitor);
+
+    if (m_markers)
+        m_markers->clearWeakMembers(visitor);
+
+    // FIXME: Oilpan: Use a weak counted set instead.
+    if (m_touchEventTargets) {
+        Vector<Node*> deadNodes;
+        for (TouchEventTargetSet::iterator it = m_touchEventTargets->begin(); it != m_touchEventTargets->end(); ++it) {
+            if (!visitor->isAlive(it->key))
+                deadNodes.append(it->key);
+        }
+        for (unsigned i = 0; i < deadNodes.size(); ++i)
+            didClearTouchEventHandlers(deadNodes[i]);
+    }
+}
+
 void Document::trace(Visitor* visitor)
 {
+    visitor->trace(m_styleSheetList);
+    visitor->trace(m_visibilityObservers);
+    visitor->registerWeakMembers<Document, &Document::clearWeakMembers>(this);
     Supplementable<Document>::trace(visitor);
+    TreeScope::trace(visitor);
     ContainerNode::trace(visitor);
 }