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

Source/core/html/ValidationMessage.h

Index: Source/core/html/ValidationMessage.h
diff --git a/Source/core/html/ValidationMessage.h b/Source/core/html/ValidationMessage.h
index 83c7f268d39f85b04afa065b755ed0098d5def20..adaa0fd2230fb78fb7c102fe555f63f736c6f03b 100644
--- a/Source/core/html/ValidationMessage.h
+++ b/Source/core/html/ValidationMessage.h
@@ -32,6 +32,7 @@
 #define ValidationMessage_h
 
 #include "core/platform/Timer.h"
+#include "heap/Handle.h"
 #include <wtf/Noncopyable.h>
 #include <wtf/OwnPtr.h>
 #include <wtf/RefPtr.h>
@@ -49,7 +50,7 @@ class ValidationMessageClient;
 class ValidationMessage {
     WTF_MAKE_NONCOPYABLE(ValidationMessage); WTF_MAKE_FAST_ALLOCATED;
 public:
-    static PassOwnPtr<ValidationMessage> create(HTMLFormControlElement*);
+    static PassOwnPtr<ValidationMessage> create(Handle<HTMLFormControlElement>);
     ~ValidationMessage();
     void updateValidationMessage(const String&);
     void requestToHideMessage();
@@ -57,13 +58,14 @@ public:
     bool shadowTreeContains(Node*) const;
 
 private:
-    ValidationMessage(HTMLFormControlElement*);
+    ValidationMessage(Handle<HTMLFormControlElement>);
     ValidationMessageClient* validationMessageClient() const;
     void setMessage(const String&);
     void setMessageDOMAndStartTimer(Timer<ValidationMessage>* = 0);
     void buildBubbleTree(Timer<ValidationMessage>*);
     void deleteBubbleTree(Timer<ValidationMessage>* = 0);
 
+    // FIXME(oilpan): Use a weak handle.
     HTMLFormControlElement* m_element;
     String m_message;
     OwnPtr<Timer<ValidationMessage> > m_timer;