Oilpan: Make the Node hierarchy RefCountedGarbageCollected instead of TreeShared.

Source/core/html/HTMLFormControlElement.cpp

Index: Source/core/html/HTMLFormControlElement.cpp
diff --git a/Source/core/html/HTMLFormControlElement.cpp b/Source/core/html/HTMLFormControlElement.cpp
index cdb8c28879ab7bee58146cd00ae2c31a6ea90024..9bc9d1d066208c6f0da2f899a2b25720ddcf877d 100644
--- a/Source/core/html/HTMLFormControlElement.cpp
+++ b/Source/core/html/HTMLFormControlElement.cpp
@@ -65,6 +65,7 @@ HTMLFormControlElement::~HTMLFormControlElement()
 {
 #if !ENABLE(OILPAN)
     setForm(0);
+    hideVisibleValidationMessage();

[haraken, 2014/05/06 15:59:42]

tkent-san: Would you confirm that this change is OK (as well as the
corresponding change in ValidationMessage)?

[tkent, 2014/05/07 00:41:19]

This line is unnecessary.  One in removedFrom is enough because detached
elements can't have validation message.

[Mads Ager (chromium), 2014/05/07 12:13:16]

The question is what happens if the entire document dies without this element
being detached. So this element is still in the document and the entire document
structure is dead. However, it looks like documentDetached is called on the
client via the Page if the document is detached in that case and that clears any
validation messages. Does that sound right to you Kent?

Remove the call.

[tkent, 2014/05/07 13:56:55]

Yeah, it's right.

 #endif
 }
 
@@ -247,6 +248,7 @@ Node::InsertionNotificationRequest HTMLFormControlElement::insertedInto(Containe
 
 void HTMLFormControlElement::removedFrom(ContainerNode* insertionPoint)
 {
+    hideVisibleValidationMessage();
     m_validationMessage = nullptr;
     m_ancestorDisabledState = AncestorDisabledStateUnknown;
     m_dataListAncestorState = Unknown;