[oilpan] Completely move HTMLFormControlElement's hierarchy to the managed heap

Source/core/html/ValidationMessage.cpp

Index: Source/core/html/ValidationMessage.cpp
diff --git a/Source/core/html/ValidationMessage.cpp b/Source/core/html/ValidationMessage.cpp
index c155fa282e730f62b6193e962ccbed94153eec14..676a09685e710229a4a9ff4ffc5cbb21f9c255ca 100644
--- a/Source/core/html/ValidationMessage.cpp
+++ b/Source/core/html/ValidationMessage.cpp
@@ -53,8 +53,8 @@ namespace WebCore {
 
 using namespace HTMLNames;
 
-ALWAYS_INLINE ValidationMessage::ValidationMessage(HTMLFormControlElement* element)
-    : m_element(element)
+ALWAYS_INLINE ValidationMessage::ValidationMessage(Handle<HTMLFormControlElement> element)
+    : m_element(element.raw())
 {
     ASSERT(m_element);
 }
@@ -69,7 +69,7 @@ ValidationMessage::~ValidationMessage()
     deleteBubbleTree();
 }
 
-PassOwnPtr<ValidationMessage> ValidationMessage::create(HTMLFormControlElement* element)
+PassOwnPtr<ValidationMessage> ValidationMessage::create(Handle<HTMLFormControlElement> element)
 {
     return adoptPtr(new ValidationMessage(element));
 }