--- a/dom/broadcastchannel/BroadcastChannel.cpp
+++ b/dom/broadcastchannel/BroadcastChannel.cpp
@@ -66,24 +66,22 @@ GetPrincipalFromWorkerPrivate(WorkerPriv
 
   return wp->GetPrincipal();
 }
 
 class InitializeRunnable final : public WorkerMainThreadRunnable
 {
 public:
   InitializeRunnable(WorkerPrivate* aWorkerPrivate, nsACString& aOrigin,
-                     PrincipalInfo& aPrincipalInfo, bool& aPrivateBrowsing,
-                     ErrorResult& aRv)
+                     PrincipalInfo& aPrincipalInfo, ErrorResult& aRv)
     : WorkerMainThreadRunnable(aWorkerPrivate,
                                NS_LITERAL_CSTRING("BroadcastChannel :: Initialize"))
     , mWorkerPrivate(GetCurrentThreadWorkerPrivate())
     , mOrigin(aOrigin)
     , mPrincipalInfo(aPrincipalInfo)
-    , mPrivateBrowsing(aPrivateBrowsing)
     , mRv(aRv)
   {
     MOZ_ASSERT(mWorkerPrivate);
   }
 
   bool MainThreadRun() override
   {
     MOZ_ASSERT(NS_IsMainThread());
@@ -122,29 +120,23 @@ public:
     }
 
     // Window doesn't exist for some kind of workers (eg: SharedWorkers)
     nsPIDOMWindowInner* window = wp->GetWindow();
     if (!window) {
       return true;
     }
 
-    nsIDocument* doc = window->GetExtantDoc();
-    if (doc) {
-      mPrivateBrowsing = nsContentUtils::IsInPrivateBrowsing(doc);
-    }
-
     return true;
   }
 
 private:
   WorkerPrivate* mWorkerPrivate;
   nsACString& mOrigin;
   PrincipalInfo& mPrincipalInfo;
-  bool& mPrivateBrowsing;
   ErrorResult& mRv;
 };
 
 class BCPostMessageRunnable final : public nsIRunnable,
                                     public nsICancelableRunnable
 {
 public:
   NS_DECL_ISUPPORTS
@@ -301,24 +293,22 @@ private:
   }
 };
 
 } // namespace
 
 BroadcastChannel::BroadcastChannel(nsPIDOMWindowInner* aWindow,
                                    const PrincipalInfo& aPrincipalInfo,
                                    const nsACString& aOrigin,
-                                   const nsAString& aChannel,
-                                   bool aPrivateBrowsing)
+                                   const nsAString& aChannel)
   : DOMEventTargetHelper(aWindow)
   , mWorkerFeature(nullptr)
   , mPrincipalInfo(new PrincipalInfo(aPrincipalInfo))
   , mOrigin(aOrigin)
   , mChannel(aChannel)
-  , mPrivateBrowsing(aPrivateBrowsing)
   , mIsKeptAlive(false)
   , mInnerID(0)
   , mState(StateActive)
 {
   // Window can be null in workers
 }
 
 BroadcastChannel::~BroadcastChannel()
@@ -339,17 +329,16 @@ BroadcastChannel::Constructor(const Glob
                               ErrorResult& aRv)
 {
   nsCOMPtr<nsPIDOMWindowInner> window =
     do_QueryInterface(aGlobal.GetAsSupports());
   // Window is null in workers.
 
   nsAutoCString origin;
   PrincipalInfo principalInfo;
-  bool privateBrowsing = false;
   WorkerPrivate* workerPrivate = nullptr;
 
   if (NS_IsMainThread()) {
     nsCOMPtr<nsIGlobalObject> incumbent = mozilla::dom::GetIncumbentGlobal();
 
     if (!incumbent) {
       aRv.Throw(NS_ERROR_FAILURE);
       return nullptr;
@@ -376,39 +365,32 @@ BroadcastChannel::Constructor(const Glob
     if (NS_WARN_IF(aRv.Failed())) {
       return nullptr;
     }
 
     aRv = PrincipalToPrincipalInfo(principal, &principalInfo);
     if (NS_WARN_IF(aRv.Failed())) {
       return nullptr;
     }
-
-    nsIDocument* doc = window->GetExtantDoc();
-    if (doc) {
-      privateBrowsing = nsContentUtils::IsInPrivateBrowsing(doc);
-    }
   } else {
     JSContext* cx = aGlobal.Context();
     workerPrivate = GetWorkerPrivateFromContext(cx);
     MOZ_ASSERT(workerPrivate);
 
     RefPtr<InitializeRunnable> runnable =
-      new InitializeRunnable(workerPrivate, origin, principalInfo,
-                             privateBrowsing, aRv);
+      new InitializeRunnable(workerPrivate, origin, principalInfo, aRv);
     runnable->Dispatch(aRv);
   }
 
   if (aRv.Failed()) {
     return nullptr;
   }
 
   RefPtr<BroadcastChannel> bc =
-    new BroadcastChannel(window, principalInfo, origin, aChannel,
-                         privateBrowsing);
+    new BroadcastChannel(window, principalInfo, origin, aChannel);
 
   // Register this component to PBackground.
   PBackgroundChild* actor = BackgroundChild::GetForCurrentThread();
   if (actor) {
     bc->ActorCreated(actor);
   } else {
     BackgroundChild::GetOrCreateForCurrentThread(bc);
   }
@@ -517,18 +499,17 @@ BroadcastChannel::ActorCreated(PBackgrou
 {
   MOZ_ASSERT(aActor);
 
   if (mState == StateClosed) {
     return;
   }
 
   PBroadcastChannelChild* actor =
-    aActor->SendPBroadcastChannelConstructor(*mPrincipalInfo, mOrigin, mChannel,
-                                             mPrivateBrowsing);
+    aActor->SendPBroadcastChannelConstructor(*mPrincipalInfo, mOrigin, mChannel);
 
   mActor = static_cast<BroadcastChannelChild*>(actor);
   MOZ_ASSERT(mActor);
 
   mActor->SetParent(this);
 
   // Flush pending messages.
   for (uint32_t i = 0; i < mPendingMessages.Length(); ++i) {

--- a/dom/broadcastchannel/BroadcastChannel.h
+++ b/dom/broadcastchannel/BroadcastChannel.h
@@ -83,18 +83,17 @@ public:
                                    ErrorResult& aRv) override;
 
   void Shutdown();
 
 private:
   BroadcastChannel(nsPIDOMWindowInner* aWindow,
                    const PrincipalInfo& aPrincipalInfo,
                    const nsACString& aOrigin,
-                   const nsAString& aChannel,
-                   bool aPrivateBrowsing);
+                   const nsAString& aChannel);
 
   ~BroadcastChannel();
 
   void PostMessageData(BroadcastChannelMessage* aData);
 
   void PostMessageInternal(JSContext* aCx, JS::Handle<JS::Value> aMessage,
                            ErrorResult& aRv);
 
@@ -111,17 +110,16 @@ private:
   nsTArray<RefPtr<BroadcastChannelMessage>> mPendingMessages;
 
   nsAutoPtr<workers::WorkerFeature> mWorkerFeature;
 
   nsAutoPtr<PrincipalInfo> mPrincipalInfo;
 
   nsCString mOrigin;
   nsString mChannel;
-  bool mPrivateBrowsing;
 
   bool mIsKeptAlive;
 
   uint64_t mInnerID;
 
   enum {
     StateActive,
     StateClosing,

--- a/ipc/glue/BackgroundChildImpl.cpp
+++ b/ipc/glue/BackgroundChildImpl.cpp
@@ -271,18 +271,17 @@ BackgroundChildImpl::DeallocPUDPSocketCh
 
 // -----------------------------------------------------------------------------
 // BroadcastChannel API
 // -----------------------------------------------------------------------------
 
 dom::PBroadcastChannelChild*
 BackgroundChildImpl::AllocPBroadcastChannelChild(const PrincipalInfo& aPrincipalInfo,
                                                  const nsCString& aOrigin,
-                                                 const nsString& aChannel,
-                                                 const bool& aPrivateBrowsing)
+                                                 const nsString& aChannel)
 {
   RefPtr<dom::BroadcastChannelChild> agent =
     new dom::BroadcastChannelChild(aOrigin);
   return agent.forget().take();
 }
 
 bool
 BackgroundChildImpl::DeallocPBroadcastChannelChild(

--- a/ipc/glue/BackgroundChildImpl.h
+++ b/ipc/glue/BackgroundChildImpl.h
@@ -99,18 +99,17 @@ protected:
   AllocPUDPSocketChild(const OptionalPrincipalInfo& aPrincipalInfo,
                        const nsCString& aFilter) override;
   virtual bool
   DeallocPUDPSocketChild(PUDPSocketChild* aActor) override;
 
   virtual PBroadcastChannelChild*
   AllocPBroadcastChannelChild(const PrincipalInfo& aPrincipalInfo,
                               const nsCString& aOrigin,
-                              const nsString& aChannel,
-                              const bool& aPrivateBrowsing) override;
+                              const nsString& aChannel) override;
 
   virtual bool
   DeallocPBroadcastChannelChild(PBroadcastChannelChild* aActor) override;
 
   virtual PServiceWorkerManagerChild*
   AllocPServiceWorkerManagerChild() override;
 
   virtual bool

--- a/ipc/glue/BackgroundParentImpl.cpp
+++ b/ipc/glue/BackgroundParentImpl.cpp
@@ -462,34 +462,29 @@ BackgroundParentImpl::DeallocPUDPSocketP
   p->Release();
   return true;
 }
 
 mozilla::dom::PBroadcastChannelParent*
 BackgroundParentImpl::AllocPBroadcastChannelParent(
                                             const PrincipalInfo& aPrincipalInfo,
                                             const nsCString& aOrigin,
-                                            const nsString& aChannel,
-                                            const bool& aPrivateBrowsing)
+                                            const nsString& aChannel)
 {
   AssertIsInMainProcess();
   AssertIsOnBackgroundThread();
 
   nsString originChannelKey;
 
   // The format of originChannelKey is:
-  //  <channelName>|pb={true,false}|<origin+OriginAttributes>
+  //  <channelName>|<origin+OriginAttributes>
 
   originChannelKey.Assign(aChannel);
 
-  if (aPrivateBrowsing) {
-    originChannelKey.AppendLiteral("|pb=true|");
-  } else {
-    originChannelKey.AppendLiteral("|pb=false|");
-  }
+  originChannelKey.AppendLiteral("|");
 
   originChannelKey.Append(NS_ConvertUTF8toUTF16(aOrigin));
 
   return new BroadcastChannelParent(originChannelKey);
 }
 
 namespace {
 
@@ -643,18 +638,17 @@ private:
 
 } // namespace
 
 bool
 BackgroundParentImpl::RecvPBroadcastChannelConstructor(
                                             PBroadcastChannelParent* actor,
                                             const PrincipalInfo& aPrincipalInfo,
                                             const nsCString& aOrigin,
-                                            const nsString& aChannel,
-                                            const bool& aPrivateBrowsing)
+                                            const nsString& aChannel)
 {
   AssertIsInMainProcess();
   AssertIsOnBackgroundThread();
 
   RefPtr<ContentParent> parent = BackgroundParent::GetContentParent(this);
 
   // If the ContentParent is null we are dealing with a same-process actor.
   if (!parent) {

--- a/ipc/glue/BackgroundParentImpl.h
+++ b/ipc/glue/BackgroundParentImpl.h
@@ -85,25 +85,23 @@ protected:
   AllocPVsyncParent() override;
 
   virtual bool
   DeallocPVsyncParent(PVsyncParent* aActor) override;
 
   virtual PBroadcastChannelParent*
   AllocPBroadcastChannelParent(const PrincipalInfo& aPrincipalInfo,
                                const nsCString& aOrigin,
-                               const nsString& aChannel,
-                               const bool& aPrivateBrowsing) override;
+                               const nsString& aChannel) override;
 
   virtual bool
   RecvPBroadcastChannelConstructor(PBroadcastChannelParent* actor,
                                    const PrincipalInfo& aPrincipalInfo,
                                    const nsCString& origin,
-                                   const nsString& channel,
-                                   const bool& aPrivateBrowsing) override;
+                                   const nsString& channel) override;
 
   virtual bool
   DeallocPBroadcastChannelParent(PBroadcastChannelParent* aActor) override;
 
   virtual PNuwaParent*
   AllocPNuwaParent() override;
 
   virtual bool

--- a/ipc/glue/PBackground.ipdl
+++ b/ipc/glue/PBackground.ipdl
@@ -74,18 +74,17 @@ parent:
   // Use only for testing!
   async FlushPendingFileDeletions();
 
   async PVsync();
 
   async PCameras();
 
   async PUDPSocket(OptionalPrincipalInfo pInfo, nsCString filter);
-  async PBroadcastChannel(PrincipalInfo pInfo, nsCString origin, nsString channel,
-                          bool privateBrowsing);
+  async PBroadcastChannel(PrincipalInfo pInfo, nsCString origin, nsString channel);
 
   async PServiceWorkerManager();
 
   async ShutdownServiceWorkerRegistrar();
 
   async PCacheStorage(Namespace aNamespace, PrincipalInfo aPrincipalInfo);
 
   async PMessagePort(nsID uuid, nsID destinationUuid, uint32_t sequenceId);