Bug 1248772 - Trigger a OS window focus in ServiceWorkerClients::OpenWindow. r=ehsan

dom/base/nsContentUtils.cpp

@@ -3829,6 +3829,22 @@ nsContentUtils::DispatchChromeEvent(nsIDocument *aDoc,
   return rv;
 }
 
+/* static */
+nsresult
+nsContentUtils::DispatchFocusChromeEvent(nsPIDOMWindowOuter* aWindow)
+{
+  MOZ_ASSERT(aWindow);
+
+  nsCOMPtr<nsIDocument> doc = aWindow->GetExtantDoc();
+  if (!doc) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return DispatchChromeEvent(doc, aWindow,
+                             NS_LITERAL_STRING("DOMServiceWorkerFocusClient"),
+                             true, true);
+}
+
 nsresult
 nsContentUtils::DispatchEventOnlyToChrome(nsIDocument* aDoc,
                                           nsISupports* aTarget,

dom/base/nsContentUtils.h

@@ -1125,6 +1125,13 @@ public:
                                       bool aCancelable,
                                       bool *aDefaultAction = nullptr);
 
+  /**
+   * Helper function for dispatching a "DOMServiceWorkerFocusClient" event to
+   * the chrome event handler of the given DOM Window. This has the effect
+   * of focusing the corresponding tab and bringing the browser window
+   * to the foreground.
+   */
+  static nsresult DispatchFocusChromeEvent(nsPIDOMWindowOuter* aWindow);
 
   /**
    * This method creates and dispatches a trusted event.

dom/workers/ServiceWorkerClients.cpp

@@ -503,6 +503,11 @@ public:
     if (NS_SUCCEEDED(rv)) {
       MOZ_ASSERT(window);
 
+      rv = nsContentUtils::DispatchFocusChromeEvent(window);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+
       WorkerPrivate* workerPrivate = mPromiseProxy->GetWorkerPrivate();
       MOZ_ASSERT(workerPrivate);
 

dom/workers/ServiceWorkerWindowClient.cpp

@@ -95,10 +95,7 @@ public:
     if (window) {
       nsCOMPtr<nsIDocument> doc = window->GetDocument();
       if (doc) {
-        nsContentUtils::DispatchChromeEvent(doc,
-                                            window->GetOuterWindow(),
-                                            NS_LITERAL_STRING("DOMServiceWorkerFocusClient"),
-                                            true, true);
+        nsContentUtils::DispatchFocusChromeEvent(window->GetOuterWindow());
         clientInfo.reset(new ServiceWorkerClientInfo(doc));
       }
     }