diff --git a/dom/performance/Performance.cpp b/dom/performance/Performance.cpp
index f3523293a4..bf36707be8 100755
--- a/dom/performance/Performance.cpp
+++ b/dom/performance/Performance.cpp
@@ -300,6 +300,28 @@ Performance::ClearMarks(const Optional<nsAString>& aName)
   ClearUserEntries(aName, NS_LITERAL_STRING("mark"));
 }
 
+// To be removed once bug 1124165 lands
+bool
+Performance::IsPerformanceTimingAttribute(const nsAString& aName) const
+{
+  // Note that toJSON is added to this list due to bug 1047848
+  static const char* attributes[] =
+    {"navigationStart", "unloadEventStart", "unloadEventEnd", "redirectStart",
+     "redirectEnd", "fetchStart", "domainLookupStart", "domainLookupEnd",
+     "connectStart", "secureConnectionStart", "connectEnd", "requestStart", "responseStart",
+     "responseEnd", "domLoading", "domInteractive",
+     "domContentLoadedEventStart", "domContentLoadedEventEnd", "domComplete",
+     "loadEventStart", "loadEventEnd", nullptr};
+
+  for (uint32_t i = 0; attributes[i]; ++i) {
+    if (aName.EqualsASCII(attributes[i])) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 DOMHighResTimeStamp
 Performance::ConvertMarkToTimestampWithString(const nsAString& aName,
                                               ErrorResult& aRv)
diff --git a/dom/performance/Performance.h b/dom/performance/Performance.h
index 6bdd42a8e8..75d164c214 100644
--- a/dom/performance/Performance.h
+++ b/dom/performance/Performance.h
@@ -117,7 +117,9 @@ public:
 
   virtual nsITimedChannel* GetChannel() const = 0;
 
-  virtual bool IsPerformanceTimingAttribute(const nsAString& aName)
+  bool IsPerformanceTimingAttribute(const nsAString& aName) const;
+
+  virtual bool IsGlobalObjectWindow() const
   {
     return false;
   }
diff --git a/dom/performance/PerformanceMainThread.cpp b/dom/performance/PerformanceMainThread.cpp
index acb69ea358..a4dbf88799 100644
--- a/dom/performance/PerformanceMainThread.cpp
+++ b/dom/performance/PerformanceMainThread.cpp
@@ -177,28 +177,6 @@ PerformanceMainThread::AddEntry(nsIHttpChannel* channel,
   }
 }
 
-// To be removed once bug 1124165 lands
-bool
-PerformanceMainThread::IsPerformanceTimingAttribute(const nsAString& aName)
-{
-  // Note that toJSON is added to this list due to bug 1047848
-  static const char* attributes[] =
-    {"navigationStart", "unloadEventStart", "unloadEventEnd", "redirectStart",
-     "redirectEnd", "fetchStart", "domainLookupStart", "domainLookupEnd",
-     "connectStart", "secureConnectionStart", "connectEnd", "requestStart", "responseStart",
-     "responseEnd", "domLoading", "domInteractive",
-     "domContentLoadedEventStart", "domContentLoadedEventEnd", "domComplete",
-     "loadEventStart", "loadEventEnd", nullptr};
-
-  for (uint32_t i = 0; attributes[i]; ++i) {
-    if (aName.EqualsASCII(attributes[i])) {
-      return true;
-    }
-  }
-
-  return false;
-}
-
 DOMHighResTimeStamp
 PerformanceMainThread::GetPerformanceTimingFromString(const nsAString& aProperty)
 {
diff --git a/dom/performance/PerformanceMainThread.h b/dom/performance/PerformanceMainThread.h
index 35fd4ab0e2..702483e9de 100644
--- a/dom/performance/PerformanceMainThread.h
+++ b/dom/performance/PerformanceMainThread.h
@@ -57,6 +57,11 @@ public:
                                 const Optional<nsAString>& aEntryType,
                                 nsTArray<RefPtr<PerformanceEntry>>& aRetval) override;
 
+  bool IsGlobalObjectWindow() const override
+  {
+    return true;
+  }
+
 protected:
   ~PerformanceMainThread();
 
@@ -67,8 +72,6 @@ protected:
 
   void InsertUserEntry(PerformanceEntry* aEntry) override;
 
-  bool IsPerformanceTimingAttribute(const nsAString& aName) override;
-
   DOMHighResTimeStamp
   GetPerformanceTimingFromString(const nsAString& aTimingName) override;
 
diff --git a/dom/performance/PerformanceMark.cpp b/dom/performance/PerformanceMark.cpp
index cd6d1bb39d..bf8d930c5d 100644
--- a/dom/performance/PerformanceMark.cpp
+++ b/dom/performance/PerformanceMark.cpp
@@ -52,7 +52,8 @@ already_AddRefed<PerformanceMark> PerformanceMark::Constructor(
     return nullptr;
   }
 
-  if (performance->IsPerformanceTimingAttribute(aMarkName)) {
+  if (performance->IsGlobalObjectWindow() &&
+      performance->IsPerformanceTimingAttribute(aMarkName)) {
     aRv.ThrowTypeError<MSG_PMO_INVALID_TIMING_ATTR>();
     return nullptr;
   }