Clean up forward declarations in Source/core/html

Source/core/html/HTMLFormElement.h

Index: Source/core/html/HTMLFormElement.h
diff --git a/Source/core/html/HTMLFormElement.h b/Source/core/html/HTMLFormElement.h
index 1772b640e8a19b13adb32930fb9b37439e6321b9..1af65dbf2e6cf3cbcde8deb1a53361d1d06e8cb5 100644
--- a/Source/core/html/HTMLFormElement.h
+++ b/Source/core/html/HTMLFormElement.h
@@ -31,20 +31,14 @@
 #include "wtf/OwnPtr.h"
 #include "wtf/WeakPtr.h"
 
-namespace WTF{
-class TextEncoding;
-}
-
 namespace blink {
 
 class Event;
 class FormAssociatedElement;
-class FormData;
 class GenericEventQueue;
 class HTMLFormControlElement;
 class HTMLFormControlsCollection;
 class HTMLImageElement;
-class HTMLInputElement;
 
 class HTMLFormElement FINAL : public HTMLElement {
     DEFINE_WRAPPERTYPEINFO();