Add UseCounters for lang and xml:lang content attributes.

Source/core/html/forms/SubmitInputType.cpp

Index: Source/core/html/forms/SubmitInputType.cpp
diff --git a/Source/core/html/forms/SubmitInputType.cpp b/Source/core/html/forms/SubmitInputType.cpp
index 926a1c7002a074b156c62ee6e5453221b44404db..3f0bf7a22d6f04c4e5650208ad13709444dc9c23 100644
--- a/Source/core/html/forms/SubmitInputType.cpp
+++ b/Source/core/html/forms/SubmitInputType.cpp
@@ -44,6 +44,7 @@ namespace blink {
 
 PassRefPtrWillBeRawPtr<InputType> SubmitInputType::create(HTMLInputElement& element)
 {
+    UseCounter::count(element.document(), UseCounter::InputTypeSubmit);
     return adoptRefWillBeNoop(new SubmitInputType(element));
 }
 
@@ -91,4 +92,10 @@ bool SubmitInputType::isTextButton() const
     return true;
 }
 
+void SubmitInputType::valueAttributeChanged()
+{
+    UseCounter::count(element().document(), UseCounter::InputTypeSubmitWithValue);
+    BaseButtonInputType::valueAttributeChanged();
+}
+
 } // namespace blink