Implement queueMicrotask()

dom/base/nsIGlobalObject.cpp

@@ -3,23 +3,30 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsIGlobalObject.h"
-
+#include "mozilla/CycleCollectedJSContext.h"
 #include "mozilla/dom/BlobURLProtocolHandler.h"
+#include "mozilla/dom/FunctionBinding.h"
 #include "mozilla/dom/ServiceWorker.h"
 #include "mozilla/dom/ServiceWorkerRegistration.h"
 #include "nsContentUtils.h"
 #include "nsThreadUtils.h"
 #include "nsGlobalWindowInner.h"
 
+using mozilla::AutoSlowOperation;
+using mozilla::CycleCollectedJSContext;
 using mozilla::DOMEventTargetHelper;
+using mozilla::ErrorResult;
+using mozilla::IgnoredErrorResult;
 using mozilla::MallocSizeOf;
 using mozilla::Maybe;
+using mozilla::MicroTaskRunnable;
 using mozilla::dom::BlobURLProtocolHandler;
 using mozilla::dom::ClientInfo;
 using mozilla::dom::ServiceWorker;
 using mozilla::dom::ServiceWorkerDescriptor;
 using mozilla::dom::ServiceWorkerRegistration;
 using mozilla::dom::ServiceWorkerRegistrationDescriptor;
+using mozilla::dom::VoidFunction;
 
 bool nsIGlobalObject::IsScriptForbidden(JSObject* aCallback,
                                         bool aIsJSImplementedWebIDL) const {
@@ -232,3 +239,28 @@ size_t nsIGlobalObject::ShallowSizeOfExcludingThis(MallocSizeOf aSizeOf) const {
   size_t rtn = mHostObjectURIs.ShallowSizeOfExcludingThis(aSizeOf);
   return rtn;
 }
+
+class QueuedMicrotask : public MicroTaskRunnable {
+ public:
+  QueuedMicrotask(nsIGlobalObject* aGlobal, VoidFunction& aCallback)
+      : mGlobal(aGlobal), mCallback(&aCallback) {}
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY void Run(AutoSlowOperation& aAso) final {
+    IgnoredErrorResult rv;
+    MOZ_KnownLive(mCallback)->Call(static_cast<ErrorResult&>(rv));
+  }
+
+  bool Suppressed() final { return mGlobal->IsInSyncOperation(); }
+
+ private:
+  nsCOMPtr<nsIGlobalObject> mGlobal;
+  RefPtr<VoidFunction> mCallback;
+};
+
+void nsIGlobalObject::QueueMicrotask(VoidFunction& aCallback) {
+  CycleCollectedJSContext* context = CycleCollectedJSContext::Get();
+  if (context) {
+    RefPtr<MicroTaskRunnable> mt = new QueuedMicrotask(this, aCallback);
+    context->DispatchToMicroTask(mt.forget());
+  }
+}

dom/base/nsIGlobalObject.h

@@ -32,6 +32,7 @@ class nsPIDOMWindowInner;
 namespace mozilla {
 class DOMEventTargetHelper;
 namespace dom {
+class VoidFunction;
 class DebuggerNotificationManager;
 class ServiceWorker;
 class ServiceWorkerRegistration;
@@ -176,6 +177,8 @@ class nsIGlobalObject : public nsISupports,
   // nullptr otherwise.
   nsPIDOMWindowInner* AsInnerWindow();
 
+  void QueueMicrotask(mozilla::dom::VoidFunction& aCallback);
+
  protected:
   virtual ~nsIGlobalObject();
 

dom/webidl/WindowOrWorkerGlobalScope.webidl

@@ -34,6 +34,9 @@ interface mixin WindowOrWorkerGlobalScope {
   long setInterval(DOMString handler, optional long timeout = 0, any... unused);
   void clearInterval(optional long handle = 0);
 
+  // microtask queuing
+  void queueMicrotask(VoidFunction callback);
+
   // ImageBitmap
   [Throws]
   Promise<ImageBitmap> createImageBitmap(ImageBitmapSource aImage);

testing/web-platform/meta/html/browsers/the-window-object/window-properties.https.html.ini

@@ -10,9 +10,6 @@
       if (os == "android") and not e10s: FAIL
       if (os == "android") and e10s: FAIL
 
-  [Window method: queueMicrotask]
-    expected: FAIL
-
   [Window unforgeable attribute: window]
     expected:
       if nightly_build: FAIL