Short-circuit initFooEvent while dispatching events.

components/script/dom/customevent.rs

@@ -65,8 +65,12 @@ impl<'a> CustomEventMethods for JSRef<'a, CustomEvent> {
                        can_bubble: bool,
                        cancelable: bool,
                        detail: JSVal) {
-        self.detail.set(detail);
         let event: JSRef<Event> = EventCast::from_ref(self);
+        if event.dispatching() {
+            return;
+        }
+
+        self.detail.set(detail);
         event.InitEvent(type_, can_bubble, cancelable);
     }
 }

components/script/dom/event.rs

@@ -219,10 +219,11 @@ impl<'a> EventMethods for JSRef<'a, Event> {
                  type_: DOMString,
                  bubbles: bool,
                  cancelable: bool) {
-        self.initialized.set(true);
         if self.dispatching.get() {
             return;
         }
+
+        self.initialized.set(true);
         self.stop_propagation.set(false);
         self.stop_immediate.set(false);
         self.canceled.set(false);

components/script/dom/keyboardevent.rs

@@ -5,7 +5,7 @@
 use dom::bindings::codegen::Bindings::KeyboardEventBinding;
 use dom::bindings::codegen::Bindings::KeyboardEventBinding::{KeyboardEventMethods, KeyboardEventConstants};
 use dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
-use dom::bindings::codegen::InheritTypes::{UIEventCast, KeyboardEventDerived};
+use dom::bindings::codegen::InheritTypes::{EventCast, UIEventCast, KeyboardEventDerived};
 use dom::bindings::error::Fallible;
 use dom::bindings::global::GlobalRef;
 use dom::bindings::global;
@@ -558,6 +558,11 @@ impl<'a> KeyboardEventMethods for JSRef<'a, KeyboardEvent> {
                          _modifiersListArg: DOMString,
                          repeat: bool,
                          _locale: DOMString) {
+        let event: JSRef<Event> = EventCast::from_ref(self);
+        if event.dispatching() {
+            return;
+        }
+
         let uievent: JSRef<UIEvent> = UIEventCast::from_ref(self);
         uievent.InitUIEvent(typeArg, canBubbleArg, cancelableArg, viewArg, 0);
         *self.key.borrow_mut() = keyArg;

components/script/dom/mouseevent.rs

@@ -5,7 +5,7 @@
 use dom::bindings::codegen::Bindings::MouseEventBinding;
 use dom::bindings::codegen::Bindings::MouseEventBinding::MouseEventMethods;
 use dom::bindings::codegen::Bindings::UIEventBinding::UIEventMethods;
-use dom::bindings::codegen::InheritTypes::{UIEventCast, MouseEventDerived};
+use dom::bindings::codegen::InheritTypes::{EventCast, UIEventCast, MouseEventDerived};
 use dom::bindings::error::Fallible;
 use dom::bindings::global::GlobalRef;
 use dom::bindings::global;
@@ -160,6 +160,11 @@ impl<'a> MouseEventMethods for JSRef<'a, MouseEvent> {
                       metaKeyArg: bool,
                       buttonArg: i16,
                       relatedTargetArg: Option<JSRef<EventTarget>>) {
+        let event: JSRef<Event> = EventCast::from_ref(self);
+        if event.dispatching() {
+            return;
+        }
+
         let uievent: JSRef<UIEvent> = UIEventCast::from_ref(self);
         uievent.InitUIEvent(typeArg, canBubbleArg, cancelableArg, viewArg, detailArg);
         self.screen_x.set(screenXArg);

components/script/dom/uievent.rs

@@ -89,6 +89,10 @@ impl<'a> UIEventMethods for JSRef<'a, UIEvent> {
                    view: Option<JSRef<Window>>,
                    detail: i32) {
         let event: JSRef<Event> = EventCast::from_ref(self);
+        if event.dispatching() {
+            return;
+        }
+
         event.InitEvent(type_, can_bubble, cancelable);
         self.view.assign(view);
         self.detail.set(detail);