Oilpan: Replace RefPtrs to Node and its subclasses in core/dom/ with Oilpan transtion types.

Source/platform/heap/Handle.h

Index: Source/platform/heap/Handle.h
diff --git a/Source/platform/heap/Handle.h b/Source/platform/heap/Handle.h
index 6a46cef73a1b9bbf1ee303b986977ceb9d7d81f2..203780194d341006cc438cfc192b83c1c6030215 100644
--- a/Source/platform/heap/Handle.h
+++ b/Source/platform/heap/Handle.h
@@ -552,7 +552,8 @@ public:
 
     T* operator->() const { return m_raw; }
     T& operator*() const { return *m_raw; }
-    operator RawPtr<T>() const { return m_raw; }
+    template<typename U>
+    operator RawPtr<U>() const { return m_raw; }

[zerny-chromium, 2014/06/04 09:28:18]

Generalizing this operator causes ambiguity since we can then convert a
Member/Persistent to a RawPtr<U> or a U*. Is it strictly needed for this change?
I found that too many protect(foo)'s had to have an added .get() for this to
work...

[tkent, 2014/06/05 00:22:27]

Without this, we need to add dozens of .get() to code like the following:

    RefPtrWillBeMember<HTMLFooElement> m_foo;
    ....
    parent->appendChild(m_foo);

With this, we need to add just one .get() for HTMLLinkElement.cpp in this CL.
Almost all instances of protect(foo) is not for Member<>.

 
     template<typename U>
     Member& operator=(const Persistent<U>& other)