Bug 1252055 P1 Make equivalent ServiceWorker DOM objects strictly equal in js. r=ehsan

dom/workers/ServiceWorker.h

@@ -27,7 +27,7 @@ ServiceWorkerVisible(JSContext* aCx, JSObject* aObj);
 
 class ServiceWorker final : public DOMEventTargetHelper
 {
-  friend class ServiceWorkerManager;
+  friend class ServiceWorkerInfo;
 public:
   NS_DECL_ISUPPORTS_INHERITED
 
@@ -68,7 +68,7 @@ public:
               ErrorResult& aRv);
 
 private:
-  // This class can only be created from the ServiceWorkerManager.
+  // This class can only be created from ServiceWorkerInfo::GetOrCreateInstance().
   ServiceWorker(nsPIDOMWindowInner* aWindow, ServiceWorkerInfo* aInfo);
 
   // This class is reference-counted and will be destroyed from Release().

dom/workers/ServiceWorkerManager.cpp

@@ -3566,7 +3566,7 @@ ServiceWorkerManager::GetServiceWorkerForScope(nsPIDOMWindowInner* aWindow,
     return NS_ERROR_DOM_NOT_FOUND_ERR;
   }
 
-  RefPtr<ServiceWorker> serviceWorker = new ServiceWorker(aWindow, info);
+  RefPtr<ServiceWorker> serviceWorker = info->GetOrCreateInstance(aWindow);
 
   serviceWorker->SetState(info->State());
   serviceWorker.forget(aServiceWorker);
@@ -3793,7 +3793,7 @@ ServiceWorkerManager::GetDocumentController(nsPIDOMWindowInner* aWindow,
 
   MOZ_ASSERT(registration->mActiveWorker);
   RefPtr<ServiceWorker> serviceWorker =
-    new ServiceWorker(aWindow, registration->mActiveWorker);
+    registration->mActiveWorker->GetOrCreateInstance(aWindow);
 
   serviceWorker.forget(aServiceWorker);
   return NS_OK;
@@ -5250,4 +5250,27 @@ ServiceWorkerInfo::GetNextID() const
   return ++gServiceWorkerInfoCurrentID;
 }
 
+already_AddRefed<ServiceWorker>
+ServiceWorkerInfo::GetOrCreateInstance(nsPIDOMWindowInner* aWindow)
+{
+  AssertIsOnMainThread();
+  MOZ_ASSERT(aWindow);
+
+  RefPtr<ServiceWorker> ref;
+
+  for (uint32_t i = 0; i < mInstances.Length(); ++i) {
+    MOZ_ASSERT(mInstances[i]);
+    if (mInstances[i]->GetOwner() == aWindow) {
+      ref = mInstances[i];
+      break;
+    }
+  }
+
+  if (!ref) {
+    ref = new ServiceWorker(aWindow, this);
+  }
+
+  return ref.forget();
+}
+
 END_WORKERS_NAMESPACE

dom/workers/ServiceWorkerManager.h

@@ -305,6 +305,9 @@ public:
 
   void
   RemoveWorker(ServiceWorker* aWorker);
+
+  already_AddRefed<ServiceWorker>
+  GetOrCreateInstance(nsPIDOMWindowInner* aWindow);
 };
 
 #define NS_SERVICEWORKERMANAGER_IMPL_IID                 \