Bug 1539524 - BroadcastChannel must bind itself to valid nsIGlobalObject in workers, r=smaug

Differential Revision: https://phabricator.services.mozilla.com/D25082

--HG--
extra : moz-landing-system : lando

dom/broadcastchannel/BroadcastChannel.cpp

@@ -198,11 +198,10 @@ class TeardownRunnableOnWorker final : public WorkerControlRunnable,
 
 }  // namespace
 
-BroadcastChannel::BroadcastChannel(nsPIDOMWindowInner* aWindow,
+BroadcastChannel::BroadcastChannel(nsIGlobalObject* aGlobal,
                                    const nsAString& aChannel)
-    : DOMEventTargetHelper(aWindow), mChannel(aChannel), mState(StateActive) {
-  // Window can be null in workers
-
+    : DOMEventTargetHelper(aGlobal), mChannel(aChannel), mState(StateActive) {
+  MOZ_ASSERT(aGlobal);
   KeepAliveIfHasListenersFor(NS_LITERAL_STRING("message"));
 }
 
@@ -219,16 +218,24 @@ JSObject* BroadcastChannel::WrapObject(JSContext* aCx,
 /* static */
 already_AddRefed<BroadcastChannel> BroadcastChannel::Constructor(
     const GlobalObject& aGlobal, const nsAString& aChannel, ErrorResult& aRv) {
-  nsCOMPtr<nsPIDOMWindowInner> window =
-      do_QueryInterface(aGlobal.GetAsSupports());
-  // Window is null in workers.
+  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
+  if (NS_WARN_IF(!global)) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
 
-  RefPtr<BroadcastChannel> bc = new BroadcastChannel(window, aChannel);
+  RefPtr<BroadcastChannel> bc = new BroadcastChannel(global, aChannel);
 
   nsAutoCString origin;
   PrincipalInfo principalInfo;
 
   if (NS_IsMainThread()) {
+    nsCOMPtr<nsPIDOMWindowInner> window = do_QueryInterface(global);
+    if (NS_WARN_IF(!window)) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return nullptr;
+    }
+
     nsCOMPtr<nsIGlobalObject> incumbent = mozilla::dom::GetIncumbentGlobal();
 
     if (!incumbent) {

dom/broadcastchannel/BroadcastChannel.h

@@ -13,7 +13,7 @@
 #include "nsTArray.h"
 #include "mozilla/RefPtr.h"
 
-class nsPIDOMWindowInner;
+class nsIGlobalObject;
 
 namespace mozilla {
 
@@ -57,7 +57,7 @@ class BroadcastChannel final : public DOMEventTargetHelper {
   void Shutdown();
 
  private:
-  BroadcastChannel(nsPIDOMWindowInner* aWindow, const nsAString& aChannel);
+  BroadcastChannel(nsIGlobalObject* aGlobal, const nsAString& aChannel);
 
   ~BroadcastChannel();