Fix formAction return value for empty formaction content attribute.

Source/core/html/HTMLFormControlElement.cpp

Index: Source/core/html/HTMLFormControlElement.cpp
diff --git a/Source/core/html/HTMLFormControlElement.cpp b/Source/core/html/HTMLFormControlElement.cpp
index 66aea16e5c23dcb11d1f472c81b9f400bb76604b..54d22d6795a6220ec8c75e90eb70ab7ad54e55d4 100644
--- a/Source/core/html/HTMLFormControlElement.cpp
+++ b/Source/core/html/HTMLFormControlElement.cpp
@@ -34,6 +34,7 @@
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLLegendElement.h"
 #include "core/html/ValidityState.h"
+#include "core/html/parser/HTMLParserIdioms.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/LayoutTheme.h"
@@ -85,6 +86,19 @@ DEFINE_TRACE(HTMLFormControlElement)
     LabelableElement::trace(visitor);
 }
 
+String HTMLFormControlElement::formAction() const
+{
+    const AtomicString& action = fastGetAttribute(formactionAttr);
+    if (action.isEmpty())
+        return document().url();
+    return document().completeURL(stripLeadingAndTrailingHTMLSpaces(action));
+}
+
+void HTMLFormControlElement::setFormAction(const AtomicString& value)
+{
+    setAttribute(formactionAttr, value);
+}
+
 String HTMLFormControlElement::formEnctype() const
 {
     const AtomicString& formEnctypeAttr = fastGetAttribute(formenctypeAttr);