Issue #1792 - Part 4: Implement constructors for the EventTarget interface.

dom/bindings/Bindings.conf

@@ -293,7 +293,6 @@ DOMInterfaces = {
     # We can also get rid of the UnwrapArg bits in
     # the dom QueryInterface (in BindingUtils.cpp) at that point.
     'hasXPConnectImpls': True,
-    'concrete': False,
     'jsImplParent': 'mozilla::DOMEventTargetHelper',
     'implicitJSContext': [ 'dispatchEvent' ]
 },

dom/events/EventTarget.cpp

@@ -7,11 +7,26 @@
 #include "mozilla/dom/Event.h"
 #include "mozilla/dom/EventTarget.h"
 #include "mozilla/dom/EventTargetBinding.h"
+#include "mozilla/dom/ConstructibleEventTarget.h"
+#include "nsIGlobalObject.h"
 #include "nsThreadUtils.h"
 
 namespace mozilla {
 namespace dom {
 
+/* static */
+already_AddRefed<EventTarget>
+EventTarget::Constructor(const GlobalObject& aGlobal, ErrorResult& aRv)
+{
+  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
+  if (!global) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return nullptr;
+  }
+  RefPtr<EventTarget> target = new ConstructibleEventTarget(global);
+  return target.forget();
+}
+
 void
 EventTarget::RemoveEventListener(const nsAString& aType,
                                  EventListener* aListener,

dom/events/EventTarget.h

@@ -42,6 +42,8 @@ public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_EVENTTARGET_IID)
 
   // WebIDL API
+  static already_AddRefed<EventTarget> Constructor(const GlobalObject& aGlobal,
+                                                   ErrorResult& aRv);
   using nsIDOMEventTarget::AddEventListener;
   using nsIDOMEventTarget::RemoveEventListener;
   using nsIDOMEventTarget::DispatchEvent;

dom/webidl/EventTarget.webidl

@@ -23,7 +23,8 @@ dictionary AddEventListenerOptions : EventListenerOptions {
   boolean once = false;
 };
 
-[Exposed=(Window,Worker,WorkerDebugger,System)]
+[Constructor,
+ Exposed=(Window,Worker,WorkerDebugger,System)]
 interface EventTarget {
   /* Passing null for wantsUntrusted means "default behavior", which
      differs in content and chrome.  In content that default boolean