Replace forward class declarations of VisiblePosition to include directives

Source/core/html/HTMLTextFormControlElement.h

Index: Source/core/html/HTMLTextFormControlElement.h
diff --git a/Source/core/html/HTMLTextFormControlElement.h b/Source/core/html/HTMLTextFormControlElement.h
index 47cd3f3c46e77040ef0c15c88aa4acffead3652a..12eb0d5918c41236a1dca144db257b7d60912e17 100644
--- a/Source/core/html/HTMLTextFormControlElement.h
+++ b/Source/core/html/HTMLTextFormControlElement.h
@@ -26,14 +26,13 @@
 #define HTMLTextFormControlElement_h
 
 #include "core/CoreExport.h"
-#include "core/editing/Position.h"
+#include "core/editing/VisiblePosition.h"
 #include "core/html/HTMLFormControlElementWithState.h"
 
 namespace blink {
 
 class ExceptionState;
 class Range;
-class VisiblePosition;
 
 enum TextFieldSelectionDirection { SelectionHasNoDirection, SelectionHasForwardDirection, SelectionHasBackwardDirection };
 enum TextFieldEventBehavior { DispatchNoEvent, DispatchChangeEvent, DispatchInputAndChangeEvent };