Add Autofill preview support for <select> input fields

Source/web/WebFormControlElement.cpp

Index: Source/web/WebFormControlElement.cpp
diff --git a/Source/web/WebFormControlElement.cpp b/Source/web/WebFormControlElement.cpp
index 585260f9128cf504a3271050c653b73089137eba..3968d035eef3a6afa8ac74c540e737edcfacd43a 100644
--- a/Source/web/WebFormControlElement.cpp
+++ b/Source/web/WebFormControlElement.cpp
@@ -119,6 +119,8 @@ void WebFormControlElement::setSuggestedValue(const WebString& value)
         unwrap<HTMLInputElement>()->setSuggestedValue(value);
     if (m_private->hasTagName(HTMLNames::textareaTag))
         unwrap<HTMLTextAreaElement>()->setSuggestedValue(value);
+    if (m_private->hasTagName(HTMLNames::selectTag))
+        unwrap<HTMLSelectElement>()->setSuggestedValue(value);
 }
 
 WebString WebFormControlElement::suggestedValue() const
@@ -127,6 +129,8 @@ WebString WebFormControlElement::suggestedValue() const
         return constUnwrap<HTMLInputElement>()->suggestedValue();
     if (m_private->hasTagName(HTMLNames::textareaTag))
         return constUnwrap<HTMLTextAreaElement>()->suggestedValue();
+    if (m_private->hasTagName(HTMLNames::selectTag))
+        return constUnwrap<HTMLSelectElement>()->suggestedValue();
     return WebString();
 }