Remove RenderTheme::supportsDataListUI.

Source/core/rendering/RenderTheme.h

Index: Source/core/rendering/RenderTheme.h
diff --git a/Source/core/rendering/RenderTheme.h b/Source/core/rendering/RenderTheme.h
index 12f765a3624ea9535ca75f321588ad52a4d5f57f..8ecd33135b279ddc5e3f742703414a96925b5523 100644
--- a/Source/core/rendering/RenderTheme.h
+++ b/Source/core/rendering/RenderTheme.h
@@ -115,9 +115,6 @@ public:
     // A method asking if the theme's controls actually care about redrawing when hovered.
     virtual bool supportsHover(const RenderStyle*) const { return false; }
 
-    // A method asking if the platform is able to show datalist suggestions for a given input type.
-    virtual bool supportsDataListUI(const AtomicString&) const;
-
 #if ENABLE(INPUT_MULTIPLE_FIELDS_UI)
     // A method asking if the platform is able to show a calendar picker for a given input type.
     virtual bool supportsCalendarPicker(const AtomicString&) const;