Move FormDataList::deleteEntry() and hasEntry() to DOMFormData.

Source/core/html/DOMFormData.h

Index: Source/core/html/DOMFormData.h
diff --git a/Source/core/html/DOMFormData.h b/Source/core/html/DOMFormData.h
index 6b4b7573e731624dfa6be72c70f04bca7b042aed..3e73cdd2ee7efa34b5a734ba5b9cb72ec4e7ecf2 100644
--- a/Source/core/html/DOMFormData.h
+++ b/Source/core/html/DOMFormData.h
@@ -68,6 +68,7 @@ public:
     // FormData interface.
     void append(const String& name, const String& value);
     void append(ExecutionContext*, const String& name, Blob*, const String& filename = String());
+    void deleteEntry(const String& name);
     void get(const String& name, FormDataEntryValue& result);
     HeapVector<FormDataEntryValue> getAll(const String& name);
     bool has(const String& name);