Add name method to Runnable trait

components/script/dom/storage.rs

@@ -181,6 +181,8 @@ impl StorageEventRunnable {
 }
 
 impl Runnable for StorageEventRunnable {
+    fn name(&self) -> &'static str { "StorageEventRunnable" }
+
     fn main_thread_handler(self: Box<StorageEventRunnable>, script_thread: &ScriptThread) {
         let this = *self;
         let storage_root = this.element.root();

components/script/script_thread.rs

@@ -200,6 +200,7 @@ impl<T: Runnable + Send> Runnable for CancellableRunnable<T> {
 
 pub trait Runnable {
     fn is_cancelled(&self) -> bool { false }
+    fn name(&self) -> &'static str { "generic runnable" }
     fn handler(self: Box<Self>) {}
     fn main_thread_handler(self: Box<Self>, _script_thread: &ScriptThread) { self.handler(); }
 }