Auto merge of #8491 - jdm:lazycompile, r=Ms2ger

Compile raw inline event handlers lazily. Resolves #8489.

Per https://html.spec.whatwg.org/multipage/webappapis.html#getting-the-current-value-of-the-event-handler and https://html.spec.whatwg.org/multipage/webappapis.html#event-handler-attributes:event-handlers-2 .

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components/script/dom/bindings/trace.rs

@@ -255,6 +255,15 @@ impl<A: JSTraceable, B: JSTraceable> JSTraceable for (A, B) {
     }
 }
 
+impl<A: JSTraceable, B: JSTraceable, C: JSTraceable> JSTraceable for (A, B, C) {
+    #[inline]
+    fn trace(&self, trc: *mut JSTracer) {
+        let (ref a, ref b, ref c) = *self;
+        a.trace(trc);
+        b.trace(trc);
+        c.trace(trc);
+    }
+}
 
 no_jsmanaged_fields!(bool, f32, f64, String, Url, AtomicBool, Uuid);
 no_jsmanaged_fields!(usize, u8, u16, u32, u64);

components/script/dom/eventdispatcher.rs

@@ -11,7 +11,7 @@ use dom::bindings::js::{JS, Root, RootedReference};
 use dom::bindings::reflector::Reflectable;
 use dom::bindings::trace::RootedVec;
 use dom::event::{Event, EventPhase};
-use dom::eventtarget::{EventListenerType, EventTarget, ListenerPhase};
+use dom::eventtarget::{CompiledEventListener, EventTarget, ListenerPhase};
 use dom::node::Node;
 use dom::virtualmethods::vtable_for;
 use dom::window::Window;
@@ -36,7 +36,7 @@ impl Drop for AutoDOMEventMarker {
     }
 }
 
-fn handle_event(window: Option<&Window>, listener: &EventListenerType,
+fn handle_event(window: Option<&Window>, listener: &CompiledEventListener,
                 current_target: &EventTarget, event: &Event) {
     let _marker;
     if let Some(window) = window {