Ladybird/AppKit: Update chrome color on theme color change

Author: https://github.com/juniorrantila
Commit: 31ff752a10
Pull-request: https://github.com/SerenityOS/serenity/pull/21150
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/bplaat
Reviewed-by: https://github.com/shannonbooth

Ladybird/AppKit/UI/LadybirdWebView.h

@@ -26,6 +26,7 @@
 - (void)loadURL:(URL const&)url;
 - (void)onLoadStart:(URL const&)url isRedirect:(BOOL)is_redirect;
 - (void)onLoadFinish:(URL const&)url;
+- (void)onThemeColorChange:(Color)color;
 
 - (void)onTitleChange:(DeprecatedString const&)title;
 - (void)onFaviconChange:(Gfx::Bitmap const&)bitmap;