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

Source/core/editing/Editor.cpp

Index: Source/core/editing/Editor.cpp
diff --git a/Source/core/editing/Editor.cpp b/Source/core/editing/Editor.cpp
index a421ee5dd24d5b976ce17be1fc047e00129ab4ba..9d68a29fcb3aa72b2b89cd5ee3921ee29251ffd1 100644
--- a/Source/core/editing/Editor.cpp
+++ b/Source/core/editing/Editor.cpp
@@ -111,8 +111,8 @@ VisibleSelection Editor::selectionForCommand(Event* event)
         return selection;
     // If the target is a text control, and the current selection is outside of its shadow tree,
     // then use the saved selection for that text control.
-    HTMLTextFormControlElement* textFormControlOfSelectionStart = enclosingTextFormControl(selection.start());
-    HTMLTextFormControlElement* textFromControlOfTarget = isHTMLTextFormControlElement(event->target()->toNode()) ? toHTMLTextFormControlElement(event->target()->toNode()) : 0;
+    Handle<HTMLTextFormControlElement> textFormControlOfSelectionStart = enclosingTextFormControl(selection.start());
+    Handle<HTMLTextFormControlElement> textFromControlOfTarget = isHTMLTextFormControlElement(event->target()->toNode()) ? toHTMLTextFormControlElement(event->target()->toNode()) : nullptr;
     if (textFromControlOfTarget && (selection.start().isNull() || textFromControlOfTarget != textFormControlOfSelectionStart)) {
         if (RefPtr<Range> range = textFromControlOfTarget->selection())
             return VisibleSelection(range.get(), DOWNSTREAM, selection.isDirectional());