Bug 1359017 - onmessageerror for MessagePort in case StructuredClone algorithm fails when deserializing, r=masayuki, r=smaug

dom/base/nsGkAtomList.h

@@ -920,6 +920,7 @@ GK_ATOM(onloadingerror, "onloadingerror")
 GK_ATOM(onpopstate, "onpopstate")
 GK_ATOM(only, "only")               // this one is not an event
 GK_ATOM(onmessage, "onmessage")
+GK_ATOM(onmessageerror, "onmessageerror")
 GK_ATOM(onmousedown, "onmousedown")
 GK_ATOM(onmouseenter, "onmouseenter")
 GK_ATOM(onmouseleave, "onmouseleave")

dom/messagechannel/MessagePort.cpp

@@ -137,6 +137,7 @@ private:
     }
 
     if (NS_WARN_IF(rv.Failed())) {
+      mPort->DispatchError();
       return rv.StealNSResult();
     }
 
@@ -148,6 +149,7 @@ private:
 
     Sequence<OwningNonNull<MessagePort>> ports;
     if (!mData->TakeTransferredPortsAsSequence(ports)) {
+      mPort->DispatchError();
       return NS_ERROR_OUT_OF_MEMORY;
     }
 
@@ -694,7 +696,7 @@ MessagePort::Entangled(nsTArray<ClonedMessageData>& aMessages)
   FallibleTArray<RefPtr<SharedMessagePortMessage>> data;
   if (NS_WARN_IF(!SharedMessagePortMessage::FromMessagesToSharedChild(aMessages,
                                                                       data))) {
-    // OOM, we cannot continue.
+    DispatchError();
     return;
   }
 
@@ -748,7 +750,7 @@ MessagePort::MessagesReceived(nsTArray<ClonedMessageData>& aMessages)
   FallibleTArray<RefPtr<SharedMessagePortMessage>> data;
   if (NS_WARN_IF(!SharedMessagePortMessage::FromMessagesToSharedChild(aMessages,
                                                                       data))) {
-    // OOM, We cannot continue.
+    DispatchError();
     return;
   }
 
@@ -1004,5 +1006,28 @@ MessagePort::ForceClose(const MessagePortIdentifier& aIdentifier)
   ForceCloseHelper::ForceClose(aIdentifier);
 }
 
+void
+MessagePort::DispatchError()
+{
+  nsCOMPtr<nsIGlobalObject> globalObject = GetParentObject();
+
+  AutoJSAPI jsapi;
+  if (!globalObject || !jsapi.Init(globalObject)) {
+    NS_WARNING("Failed to initialize AutoJSAPI object.");
+    return;
+  }
+
+  RootedDictionary<MessageEventInit> init(jsapi.cx());
+  init.mBubbles = false;
+  init.mCancelable = false;
+
+  RefPtr<Event> event =
+    MessageEvent::Constructor(this, NS_LITERAL_STRING("messageerror"), init);
+  event->SetTrusted(true);
+
+  bool dummy;
+  DispatchEvent(event, &dummy);
+}
+
 } // namespace dom
 } // namespace mozilla

dom/messagechannel/MessagePort.h

@@ -74,6 +74,8 @@ public:
 
   void SetOnmessage(EventHandlerNonNull* aCallback);
 
+  IMPL_EVENT_HANDLER(messageerror)
+
   // Non WebIDL methods
 
   void UnshippedEntangle(MessagePort* aEntangledPort);
@@ -147,6 +149,8 @@ private:
   // Dispatch events from the Message Queue using a nsRunnable.
   void Dispatch();
 
+  void DispatchError();
+
   void StartDisentangling();
   void Disentangle();
 

dom/webidl/MessagePort.webidl

@@ -17,5 +17,6 @@ interface MessagePort : EventTarget {
 
   // event handlers
   attribute EventHandler onmessage;
+  attribute EventHandler onmessageerror;
 };
 // MessagePort implements Transferable;