Set element value to its default value on reset

Source/core/html/HTMLInputElement.cpp

Index: Source/core/html/HTMLInputElement.cpp
diff --git a/Source/core/html/HTMLInputElement.cpp b/Source/core/html/HTMLInputElement.cpp
index d0704564663d4357c2add46e8a78209cd188920e..b3af7171966c89acfbec0c72d4ef088d222e51c7 100644
--- a/Source/core/html/HTMLInputElement.cpp
+++ b/Source/core/html/HTMLInputElement.cpp
@@ -839,7 +839,7 @@ String HTMLInputElement::resultForDialogSubmit()
 void HTMLInputElement::resetImpl()
 {
     if (m_inputType->storesValueSeparateFromAttribute()) {
-        setValue(String());
+        setValue(defaultValue());

[tkent, 2014/10/29 00:28:29]

This is a wrong fix.
Setting a null string to the value means the value refers to the default value. 
This change breaks the long-standing assumption.

         setNeedsValidityCheck();
     }