Oilpan: move DOM string collection objects to the Oilpan heap.

Source/core/html/LabelableElement.h

Index: Source/core/html/LabelableElement.h
diff --git a/Source/core/html/LabelableElement.h b/Source/core/html/LabelableElement.h
index 18f44085a74a637fb81ad0d8de4a4c99072290c2..922de911bf7ccebd1465126e5d1d228869c38622 100644
--- a/Source/core/html/LabelableElement.h
+++ b/Source/core/html/LabelableElement.h
@@ -43,6 +43,8 @@ public:
     PassRefPtr<NodeList> labels();
     virtual bool supportLabels() const { return false; }
 
+    virtual void trace(Visitor* visitor) OVERRIDE { HTMLElement::trace(visitor); }

[Mads Ager (chromium), 2014/04/29 09:05:14]

You don't need this one I think. The explicit call of a super trace method will
do the right thing here. It will call the inherited one so you don't need this
dummy trace override.

[haraken, 2014/04/29 09:22:56]

We'll need the trace method anyway in the near future, since there are a couple
of elements that inherit LabelableElement.

For the Node/CSS hierarchy, I'd prefer to just implement a perfect trace chain
instead of assessing what class does not need to have a trace method.

[sof, 2014/04/29 09:29:34]

(The plugin wanting such chaining was the direct reason for adding it now.)

+
 protected:
     LabelableElement(const QualifiedName& tagName, Document&);