Split NativeThemeAura into Overlay and NonOverlay versions.

ui/native_theme/native_theme.h

Index: ui/native_theme/native_theme.h
diff --git a/ui/native_theme/native_theme.h b/ui/native_theme/native_theme.h
index 5ed382a0a38df7e1e0dd8ec2927189aa2e0e9a7e..968d6ab6ffbb8ab26dbca9f0a396a1dfe3a1667d 100644
--- a/ui/native_theme/native_theme.h
+++ b/ui/native_theme/native_theme.h
@@ -361,7 +361,7 @@ class NATIVE_THEME_EXPORT NativeTheme {
   // not thread safe and should only be called from the UI thread. Each port of
   // NativeTheme should provide its own implementation of this function,
   // returning the port's subclass.
-  static NativeTheme* GetInstanceForWeb();
+  static NativeTheme* GetInstanceForWeb(bool use_overlay_scrollbars);
 
   // Add or remove observers to be notified when the native theme changes.
   void AddObserver(NativeThemeObserver* observer);