diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index 79e3c69f010..0a64e0acf89 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -1509,7 +1509,6 @@ nsGlobalWindow::FreeInnerObjects()
   }
 
   // Remove our reference to the document and the document principal.
-  mDoc = nullptr;
   mFocusedNode = nullptr;
 
   if (mApplicationCache) {
@@ -8911,6 +8910,9 @@ NS_IMPL_REMOVE_SYSTEM_EVENT_LISTENER(nsGlobalWindow)
 NS_IMETHODIMP
 nsGlobalWindow::DispatchEvent(nsIDOMEvent* aEvent, bool* aRetVal)
 {
+  MOZ_ASSERT(!IsInnerWindow() || IsCurrentInnerWindow(),
+             "We should only fire events on the current inner window.");
+
   FORWARD_TO_INNER(DispatchEvent, (aEvent, aRetVal), NS_OK);
 
   if (!mDoc) {
@@ -9040,10 +9042,7 @@ nsIScriptContext*
 nsGlobalWindow::GetContextForEventHandlers(nsresult* aRv)
 {
   *aRv = NS_ERROR_UNEXPECTED;
-  if (IsInnerWindow()) {
-    nsPIDOMWindow* outer = GetOuterWindow();
-    NS_ENSURE_TRUE(outer && outer->GetCurrentInnerWindow() == this, nullptr);
-  }
+  NS_ENSURE_TRUE(!IsInnerWindow() || IsCurrentInnerWindow(), nullptr);
 
   nsIScriptContext* scx;
   if ((scx = GetContext())) {
@@ -10699,7 +10698,7 @@ nsGlobalWindow::Observe(nsISupports* aSubject, const char* aTopic,
       // need to fire only one idle event while the window is frozen.
       mNotifyIdleObserversIdleOnThaw = true;
       mNotifyIdleObserversActiveOnThaw = false;
-    } else if (mOuterWindow && mOuterWindow->GetCurrentInnerWindow() == this) {
+    } else if (IsCurrentInnerWindow()) {
       HandleIdleActiveEvent();
     }
     return NS_OK;
@@ -10710,13 +10709,17 @@ nsGlobalWindow::Observe(nsISupports* aSubject, const char* aTopic,
     if (IsFrozen()) {
       mNotifyIdleObserversActiveOnThaw = true;
       mNotifyIdleObserversIdleOnThaw = false;
-    } else if (mOuterWindow && mOuterWindow->GetCurrentInnerWindow() == this) {
+    } else if (IsCurrentInnerWindow()) {
       ScheduleActiveTimerCallback();
     }
     return NS_OK;
   }
 
-  if (IsInnerWindow() && !nsCRT::strcmp(aTopic, "dom-storage2-changed")) {
+  if (!nsCRT::strcmp(aTopic, "dom-storage2-changed")) {
+    if (!IsInnerWindow() || !IsCurrentInnerWindow()) {
+      return NS_OK;
+    }
+
     nsIPrincipal *principal;
     nsresult rv;
 
diff --git a/dom/base/nsPIDOMWindow.h b/dom/base/nsPIDOMWindow.h
index 45f524d779f..78914a8ad34 100644
--- a/dom/base/nsPIDOMWindow.h
+++ b/dom/base/nsPIDOMWindow.h
@@ -327,6 +327,15 @@ public:
     return mIsInnerWindow;
   }
 
+  // Returns true if this object has an outer window and it is the current inner
+  // window of that outer. Only call this on inner windows.
+  bool IsCurrentInnerWindow() const
+  {
+    MOZ_ASSERT(IsInnerWindow(),
+               "It doesn't make sense to call this on outer windows.");
+    return mOuterWindow && mOuterWindow->GetCurrentInnerWindow() == this;
+  }
+
   bool IsOuterWindow() const
   {
     return !IsInnerWindow();
diff --git a/dom/gamepad/GamepadService.cpp b/dom/gamepad/GamepadService.cpp
index ba118b3d09a..879b6b3cedf 100644
--- a/dom/gamepad/GamepadService.cpp
+++ b/dom/gamepad/GamepadService.cpp
@@ -209,7 +209,7 @@ GamepadService::NewButtonEvent(uint32_t aIndex, uint32_t aButton, bool aPressed,
     --i;
 
     // Only send events to non-background windows
-    if (!listeners[i]->GetOuterWindow() ||
+    if (!listeners[i]->IsCurrentInnerWindow() ||
         listeners[i]->GetOuterWindow()->IsBackground()) {
       continue;
     }
@@ -274,7 +274,7 @@ GamepadService::NewAxisMoveEvent(uint32_t aIndex, uint32_t aAxis, double aValue)
     --i;
 
     // Only send events to non-background windows
-    if (!listeners[i]->GetOuterWindow() ||
+    if (!listeners[i]->IsCurrentInnerWindow() ||
         listeners[i]->GetOuterWindow()->IsBackground()) {
       continue;
     }
@@ -340,7 +340,7 @@ GamepadService::NewConnectionEvent(uint32_t aIndex, bool aConnected)
       --i;
 
       // Only send events to non-background windows
-      if (!listeners[i]->GetOuterWindow() ||
+      if (!listeners[i]->IsCurrentInnerWindow() ||
           listeners[i]->GetOuterWindow()->IsBackground()) {
         continue;
       }
@@ -525,6 +525,7 @@ GamepadServiceTest::CreateService()
 GamepadServiceTest::GamepadServiceTest()
 {
   /* member initializers and constructor code */
+  nsRefPtr<GamepadService> service = GamepadService::GetService();
 }
 
 /* uint32_t addGamepad (in string id, in unsigned long mapping, in unsigned long numButtons, in unsigned long numAxes); */