LibWeb: Add opt-in tracing of invalidate_layout_tree() calls with reason

Author: https://github.com/awesomekling
Commit: 415079bc11
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3852

Libraries/LibWeb/DOM/ShadowRoot.cpp

@@ -88,7 +88,7 @@ WebIDL::ExceptionOr<void> ShadowRoot::set_inner_html(StringView value)
 
         if (this->is_connected()) {
             // NOTE: Since the DOM has changed, we have to rebuild the layout tree.
-            this->document().invalidate_layout_tree();
+            this->document().invalidate_layout_tree(InvalidateLayoutTreeReason::ShadowRootSetInnerHTML);
         }
     }