diff --git a/dom/workers/ServiceWorkerContainer.cpp b/dom/workers/ServiceWorkerContainer.cpp
index ee3faddb8077..11081d84bdf9 100644
--- a/dom/workers/ServiceWorkerContainer.cpp
+++ b/dom/workers/ServiceWorkerContainer.cpp
@@ -113,13 +113,32 @@ ServiceWorkerContainer::Register(const nsAString& aScriptURL,
     return nullptr;
   }
 
-  nsCOMPtr<nsPIDOMWindow> window = GetOwner();
-  MOZ_ASSERT(window);
+  nsCOMPtr<nsIURI> baseURI;
+
+  nsIDocument* doc = GetEntryDocument();
+  if (doc) {
+    baseURI = doc->GetBaseURI();
+  } else {
+    // XXXnsm. One of our devtools browser test calls register() from a content
+    // script where there is no valid entry document. Use the window to resolve
+    // the uri in that case.
+    nsCOMPtr<nsPIDOMWindow> window = GetOwner();
+    nsCOMPtr<nsPIDOMWindow> outerWindow;
+    if (window && (outerWindow = window->GetOuterWindow()) &&
+        outerWindow->GetServiceWorkersTestingEnabled()) {
+      baseURI = window->GetDocBaseURI();
+    }
+  }
+
+
+  if (!baseURI) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return nullptr;
+  }
 
   nsresult rv;
   nsCOMPtr<nsIURI> scriptURI;
-  rv = NS_NewURI(getter_AddRefs(scriptURI), aScriptURL, nullptr,
-                 window->GetDocBaseURI());
+  rv = NS_NewURI(getter_AddRefs(scriptURI), aScriptURL, nullptr, baseURI);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     aRv.ThrowTypeError(MSG_INVALID_URL, &aScriptURL);
     return nullptr;
@@ -143,17 +162,19 @@ ServiceWorkerContainer::Register(const nsAString& aScriptURL,
   } else {
     // Step 5. Parse against entry settings object's base URL.
     rv = NS_NewURI(getter_AddRefs(scopeURI), aOptions.mScope.Value(),
-                   nullptr, window->GetDocBaseURI());
+                   nullptr, baseURI);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       nsAutoCString spec;
-      if (window->GetDocBaseURI()) {
-        window->GetDocBaseURI()->GetSpec(spec);
-      }
+      baseURI->GetSpec(spec);
       aRv.ThrowTypeError(MSG_INVALID_SCOPE, &aOptions.mScope.Value(), &spec);
       return nullptr;
     }
   }
 
+  // The spec says that the "client" passed to Register() must be the global
+  // where the ServiceWorkerContainer was retrieved from.
+  nsCOMPtr<nsPIDOMWindow> window = GetOwner();
+  MOZ_ASSERT(window);
   aRv = swm->Register(window, scopeURI, scriptURI, getter_AddRefs(promise));
   if (aRv.Failed()) {
     return nullptr;
diff --git a/testing/web-platform/mozilla/meta/service-workers/service-worker/controller-on-reload.https.html.ini b/testing/web-platform/mozilla/meta/service-workers/service-worker/controller-on-reload.https.html.ini
deleted file mode 100644
index b9a5b66c2327..000000000000
--- a/testing/web-platform/mozilla/meta/service-workers/service-worker/controller-on-reload.https.html.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[controller-on-reload.https.html]
-  type: testharness
-  [controller is set upon reload after registration]
-    expected: FAIL
-
diff --git a/testing/web-platform/mozilla/meta/service-workers/service-worker/fetch-event-async-respond-with.https.html.ini b/testing/web-platform/mozilla/meta/service-workers/service-worker/fetch-event-async-respond-with.https.html.ini
index dcee8d7d5967..1755750ac752 100644
--- a/testing/web-platform/mozilla/meta/service-workers/service-worker/fetch-event-async-respond-with.https.html.ini
+++ b/testing/web-platform/mozilla/meta/service-workers/service-worker/fetch-event-async-respond-with.https.html.ini
@@ -3,3 +3,4 @@
   expected: OK
   [Calling respondWith asynchronously throws an exception]
     expected: FAIL
+
diff --git a/testing/web-platform/mozilla/meta/service-workers/service-worker/registration-iframe.https.html.ini b/testing/web-platform/mozilla/meta/service-workers/service-worker/registration-iframe.https.html.ini
deleted file mode 100644
index 4145809bdfdf..000000000000
--- a/testing/web-platform/mozilla/meta/service-workers/service-worker/registration-iframe.https.html.ini
+++ /dev/null
@@ -1,11 +0,0 @@
-[registration-iframe.https.html]
-  type: testharness
-  [Subframe's container's register method should use calling frame's document's url as a base url for parsing its script url and scope url - normal case]
-    expected: FAIL
-
-  [Subframe's container's register method should use calling frame's document's url as a base url for parsing its script url and scope url - error case]
-    expected: FAIL
-
-  [A scope url should start with the given script url]
-    expected: FAIL
-
diff --git a/testing/web-platform/mozilla/tests/service-workers/service-worker/registration-iframe.https.html b/testing/web-platform/mozilla/tests/service-workers/service-worker/registration-iframe.https.html
index fe4f30d95a21..fb60afe84975 100644
--- a/testing/web-platform/mozilla/tests/service-workers/service-worker/registration-iframe.https.html
+++ b/testing/web-platform/mozilla/tests/service-workers/service-worker/registration-iframe.https.html
@@ -68,7 +68,7 @@ async_test(function(t) {
         assert_unreached('register() should reject');
       },
       function(e) {
-        assert_equals(e.name, 'NetworkError');
+        assert_equals(e.name, 'TypeError');
         frame.remove();
         return service_worker_unregister_and_done(t, scope);
       })