Move most of the [Pass]RefPtr's of CSSPrimitiveValue to our transition types.

Source/wtf/RawPtr.h

Index: Source/wtf/RawPtr.h
diff --git a/Source/wtf/RawPtr.h b/Source/wtf/RawPtr.h
index c4723671a6094cce84803076230c43a5ebb6d644..8c111eafeaad4086755b00e3211ba56de2f67afa 100644
--- a/Source/wtf/RawPtr.h
+++ b/Source/wtf/RawPtr.h
@@ -55,7 +55,12 @@ public:
     T* get() const { return m_ptr; }
     void clear() { m_ptr = 0; }
     // FIXME: oilpan: Remove release and leakRef once we remove RefPtrWillBeRawPtr.
-    RawPtr<T> release() const { return m_ptr; }
+    RawPtr<T> release()
+    {
+        RawPtr<T> tmp = m_ptr;
+        m_ptr = 0;
+        return tmp;
+    }
     T* leakRef()
     {
         T* ptr = m_ptr;