spec compliant active parser concept

components/script/dom/servoparser/mod.rs

@@ -344,6 +344,11 @@ impl ServoParser {
         self.document.set_ready_state(DocumentReadyState::Interactive);
     }
 
+    // https://html.spec.whatwg.org/multipage/#active-parser
+    pub fn is_active(&self) -> bool {
+        self.script_nesting_level() > 0 && !self.aborted.get()
+    }
+
     #[allow(unrooted_must_root)]
     fn new_inherited(document: &Document,
                      tokenizer: Tokenizer,