diff --git a/dom/base/CallState.h b/dom/base/CallState.h
new file mode 100644
index 000000000000..e9c312dbe41f
--- /dev/null
+++ b/dom/base/CallState.h
@@ -0,0 +1,23 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_CallState_h
+#define mozilla_CallState_h
+
+namespace mozilla {
+
+// An enum class to be used for returned value of callback functions.  If Stop
+// is returned from the callback function, caller stops calling further
+// children. If Continue is returned then caller will keep calling further
+// children.
+enum class CallState {
+  Continue,
+  Stop,
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_CallSate_h
diff --git a/dom/base/moz.build b/dom/base/moz.build
index d1409e9c7feb..627b6a3e8fe1 100644
--- a/dom/base/moz.build
+++ b/dom/base/moz.build
@@ -121,6 +121,7 @@ if CONFIG['MOZ_WEBRTC']:
     ]
 
 EXPORTS.mozilla += [
+    'CallState.h',
     'ContentIterator.h',
     'CORSMode.h',
     'FlushType.h',
diff --git a/dom/base/nsGlobalWindowInner.cpp b/dom/base/nsGlobalWindowInner.cpp
index f26abc9bc7d2..948dd3c3ca89 100644
--- a/dom/base/nsGlobalWindowInner.cpp
+++ b/dom/base/nsGlobalWindowInner.cpp
@@ -2262,8 +2262,7 @@ bool nsGlobalWindowInner::HasOpenerForInitialContentBrowser() {
   FORWARD_TO_OUTER(HasOpenerForInitialContentBrowser, (), false);
 }
 
-nsGlobalWindowInner::CallState
-nsGlobalWindowInner::ShouldReportForServiceWorkerScopeInternal(
+CallState nsGlobalWindowInner::ShouldReportForServiceWorkerScopeInternal(
     const nsACString& aScope, bool* aResultOut) {
   MOZ_DIAGNOSTIC_ASSERT(aResultOut);
 
@@ -5342,8 +5341,7 @@ void nsGlobalWindowInner::SyncStateFromParentWindow() {
 }
 
 template <typename Method, typename... Args>
-nsGlobalWindowInner::CallState nsGlobalWindowInner::CallOnChildren(
-    Method aMethod, Args&... aArgs) {
+CallState nsGlobalWindowInner::CallOnChildren(Method aMethod, Args&... aArgs) {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(IsCurrentInnerWindow());
 
diff --git a/dom/base/nsGlobalWindowInner.h b/dom/base/nsGlobalWindowInner.h
index e3e3dbc22479..1e62044cf942 100644
--- a/dom/base/nsGlobalWindowInner.h
+++ b/dom/base/nsGlobalWindowInner.h
@@ -40,6 +40,7 @@
 #include "mozilla/dom/StorageEvent.h"
 #include "mozilla/dom/StorageEventBinding.h"
 #include "mozilla/dom/UnionTypes.h"
+#include "mozilla/CallState.h"
 #include "mozilla/ErrorResult.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/GuardObjects.h"
@@ -1033,36 +1034,25 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   bool IsPopupSpamWindow();
 
  private:
-  // A type that methods called by CallOnChildren can return.  If Stop
-  // is returned then CallOnChildren will stop calling further children.
-  // If Continue is returned then CallOnChildren will keep calling further
-  // children.
-  enum class CallState {
-    Continue,
-    Stop,
-  };
-
   // Call the given method on the immediate children of this window.  The
   // CallState returned by the last child method invocation is returned or
   // CallState::Continue if the method returns void.
   template <typename Method, typename... Args>
-  CallState CallOnChildren(Method aMethod, Args&... aArgs);
+  mozilla::CallState CallOnChildren(Method aMethod, Args&... aArgs);
 
   // Helper to convert a void returning child method into an implicit
   // CallState::Continue value.
   template <typename Return, typename Method, typename... Args>
-  typename std::enable_if<std::is_void<Return>::value,
-                          nsGlobalWindowInner::CallState>::type
+  typename std::enable_if<std::is_void<Return>::value, mozilla::CallState>::type
   CallChild(nsGlobalWindowInner* aWindow, Method aMethod, Args&... aArgs) {
     (aWindow->*aMethod)(aArgs...);
-    return nsGlobalWindowInner::CallState::Continue;
+    return mozilla::CallState::Continue;
   }
 
   // Helper that passes through the CallState value from a child method.
   template <typename Return, typename Method, typename... Args>
-  typename std::enable_if<
-      std::is_same<Return, nsGlobalWindowInner::CallState>::value,
-      nsGlobalWindowInner::CallState>::type
+  typename std::enable_if<std::is_same<Return, mozilla::CallState>::value,
+                          mozilla::CallState>::type
   CallChild(nsGlobalWindowInner* aWindow, Method aMethod, Args&... aArgs) {
     return (aWindow->*aMethod)(aArgs...);
   }
@@ -1070,8 +1060,8 @@ class nsGlobalWindowInner final : public mozilla::dom::EventTarget,
   void FreezeInternal();
   void ThawInternal();
 
-  CallState ShouldReportForServiceWorkerScopeInternal(const nsACString& aScope,
-                                                      bool* aResultOut);
+  mozilla::CallState ShouldReportForServiceWorkerScopeInternal(
+      const nsACString& aScope, bool* aResultOut);
 
  public:
   // Timeout Functions