new file mode 100644
--- /dev/null
+++ b/dom/base/Timeout.cpp
@@ -0,0 +1,90 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+
+#include "Timeout.h"
+
+#include "nsGlobalWindow.h"
+#include "nsIScriptTimeoutHandler.h"
+#include "nsITimer.h"
+#include "nsPIDOMWindow.h"
+
+namespace mozilla {
+namespace dom {
+
+Timeout::Timeout()
+  : mCleared(false),
+    mRunning(false),
+    mIsInterval(false),
+    mPublicId(0),
+    mInterval(0),
+    mFiringDepth(0),
+    mNestingLevel(0),
+    mPopupState(openAllowed)
+{
+  MOZ_COUNT_CTOR(Timeout);
+}
+
+Timeout::~Timeout()
+{
+  if (mTimer) {
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+
+  MOZ_COUNT_DTOR(Timeout);
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(Timeout)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Timeout)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mWindow)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mPrincipal)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mScriptHandler)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(Timeout)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWindow)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPrincipal)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mScriptHandler)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(Timeout, AddRef)
+NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(Timeout, Release)
+
+nsresult
+Timeout::InitTimer(uint32_t aDelay)
+{
+  return mTimer->InitWithNameableFuncCallback(
+    nsGlobalWindow::TimerCallback, this, aDelay,
+    nsITimer::TYPE_ONE_SHOT, Timeout::TimerNameCallback);
+}
+
+// static
+void
+Timeout::TimerNameCallback(nsITimer* aTimer, void* aClosure, char* aBuf,
+                           size_t aLen)
+{
+  RefPtr<Timeout> timeout = (Timeout*)aClosure;
+
+  const char* filename;
+  uint32_t lineNum, column;
+  timeout->mScriptHandler->GetLocation(&filename, &lineNum, &column);
+  snprintf(aBuf, aLen, "[content] %s:%u:%u", filename, lineNum, column);
+}
+
+
+// Return true if this timeout has a refcount of 1. This is used to check
+// that dummy_timeout doesn't leak from nsGlobalWindow::RunTimeout.
+#ifdef DEBUG
+bool
+Timeout::HasRefCntOne() const
+{
+  return mRefCnt.get() == 1;
+}
+#endif // DEBUG
+
+} // namespace dom
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/dom/base/Timeout.h
@@ -0,0 +1,97 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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_dom_timeout_h
+#define mozilla_dom_timeout_h
+
+#include "mozilla/LinkedList.h"
+#include "mozilla/TimeStamp.h"
+#include "nsCOMPtr.h"
+#include "nsCycleCollectionParticipant.h"
+
+class nsGlobalWindow;
+class nsIPrincipal;
+class nsIScriptTimeoutHandler;
+class nsITimer;
+
+namespace mozilla {
+namespace dom {
+
+/*
+ * Timeout struct that holds information about each script
+ * timeout.  Holds a strong reference to an nsIScriptTimeoutHandler, which
+ * abstracts the language specific cruft.
+ */
+class Timeout final
+  : public LinkedListElement<Timeout>
+{
+public:
+  Timeout();
+
+  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(Timeout)
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(Timeout)
+
+  nsresult InitTimer(uint32_t aDelay);
+
+  static void TimerNameCallback(nsITimer* aTimer, void* aClosure, char* aBuf,
+                                size_t aLen);
+
+#ifdef DEBUG
+  bool HasRefCntOne() const;
+#endif // DEBUG
+
+  // Window for which this timeout fires
+  RefPtr<nsGlobalWindow> mWindow;
+
+  // The actual timer object
+  nsCOMPtr<nsITimer> mTimer;
+
+  // True if the timeout was cleared
+  bool mCleared;
+
+  // True if this is one of the timeouts that are currently running
+  bool mRunning;
+
+  // True if this is a repeating/interval timer
+  bool mIsInterval;
+
+  // Returned as value of setTimeout()
+  uint32_t mPublicId;
+
+  // Interval in milliseconds
+  uint32_t mInterval;
+
+  // mWhen and mTimeRemaining can't be in a union, sadly, because they
+  // have constructors.
+  // Nominal time to run this timeout.  Use only when timeouts are not
+  // suspended.
+  TimeStamp mWhen;
+  // Remaining time to wait.  Used only when timeouts are suspended.
+  TimeDuration mTimeRemaining;
+
+  // Principal with which to execute
+  nsCOMPtr<nsIPrincipal> mPrincipal;
+
+  // stack depth at which timeout is firing
+  uint32_t mFiringDepth;
+
+  uint32_t mNestingLevel;
+
+  // The popup state at timeout creation time if not created from
+  // another timeout
+  PopupControlState mPopupState;
+
+  // The language-specific information about the callback.
+  nsCOMPtr<nsIScriptTimeoutHandler> mScriptHandler;
+
+private:
+  ~Timeout();
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_timeout_h

--- a/dom/base/moz.build
+++ b/dom/base/moz.build
@@ -203,16 +203,17 @@ EXPORTS.mozilla.dom += [
     'ScreenOrientation.h',
     'ScriptSettings.h',
     'ShadowRoot.h',
     'StructuredCloneHolder.h',
     'StructuredCloneTags.h',
     'StyleSheetList.h',
     'SubtleCrypto.h',
     'Text.h',
+    'Timeout.h',
     'TreeWalker.h',
     'WebKitCSSMatrix.h',
     'WebSocket.h',
     'WindowOrientationObserver.h',
 ]
 
 UNIFIED_SOURCES += [
     'AnonymousContent.cpp',
@@ -345,16 +346,17 @@ UNIFIED_SOURCES += [
     'ScriptSettings.cpp',
     'ShadowRoot.cpp',
     'StructuredCloneHolder.cpp',
     'StyleSheetList.cpp',
     'SubtleCrypto.cpp',
     'Text.cpp',
     'TextInputProcessor.cpp',
     'ThirdPartyUtil.cpp',
+    'Timeout.cpp',
     'TreeWalker.cpp',
     'WebKitCSSMatrix.cpp',
     'WebSocket.cpp',
     'WindowNamedPropertiesHandler.cpp',
     'WindowOrientationObserver.cpp',
 ]
 
 if CONFIG['MOZ_WEBRTC']:

--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -16,16 +16,17 @@
 #include "nsScreen.h"
 #include "nsHistory.h"
 #include "nsDOMNavigationTiming.h"
 #include "nsIDOMStorageManager.h"
 #include "mozilla/dom/DOMStorage.h"
 #include "mozilla/dom/Performance.h"
 #include "mozilla/dom/StorageEvent.h"
 #include "mozilla/dom/StorageEventBinding.h"
+#include "mozilla/dom/Timeout.h"
 #include "mozilla/IntegerPrintfMacros.h"
 #if defined(MOZ_WIDGET_ANDROID) || defined(MOZ_WIDGET_GONK)
 #include "mozilla/dom/WindowOrientationObserver.h"
 #endif
 #include "nsDOMOfflineResourceList.h"
 #include "nsError.h"
 #include "nsIIdleService.h"
 #include "nsISizeOfEventTarget.h"
@@ -498,81 +499,16 @@ private:
 
   // This reference is non-owning and safe because it's cleared by
   // nsGlobalWindow::CleanUp().
   nsGlobalWindow* MOZ_NON_OWNING_REF mWindow;
 };
 
 NS_IMPL_ISUPPORTS(nsGlobalWindowObserver, nsIObserver, nsIInterfaceRequestor)
 
-nsTimeout::nsTimeout()
-  : mCleared(false),
-    mRunning(false),
-    mIsInterval(false),
-    mPublicId(0),
-    mInterval(0),
-    mFiringDepth(0),
-    mNestingLevel(0),
-    mPopupState(openAllowed)
-{
-#ifdef DEBUG_jst
-  {
-    extern int gTimeoutCnt;
-
-    ++gTimeoutCnt;
-  }
-#endif
-
-  MOZ_COUNT_CTOR(nsTimeout);
-}
-
-nsTimeout::~nsTimeout()
-{
-#ifdef DEBUG_jst
-  {
-    extern int gTimeoutCnt;
-
-    --gTimeoutCnt;
-  }
-#endif
-
-  if (mTimer) {
-    mTimer->Cancel();
-    mTimer = nullptr;
-  }
-
-  MOZ_COUNT_DTOR(nsTimeout);
-}
-
-NS_IMPL_CYCLE_COLLECTION_CLASS(nsTimeout)
-
-NS_IMPL_CYCLE_COLLECTION_UNLINK_0(nsTimeout)
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsTimeout)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mWindow)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mScriptHandler)
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
-NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(nsTimeout, AddRef)
-NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(nsTimeout, Release)
-
-nsresult
-nsTimeout::InitTimer(uint32_t aDelay)
-{
-  return mTimer->InitWithNameableFuncCallback(
-    nsGlobalWindow::TimerCallback, this, aDelay,
-    nsITimer::TYPE_ONE_SHOT, nsGlobalWindow::TimerNameCallback);
-}
-
-// Return true if this timeout has a refcount of 1. This is used to check
-// that dummy_timeout doesn't leak from nsGlobalWindow::RunTimeout.
-bool
-nsTimeout::HasRefCntOne()
-{
-  return mRefCnt.get() == 1;
-}
-
 static already_AddRefed<nsIVariant>
 CreateVoidVariant()
 {
   RefPtr<nsVariantCC> writable = new nsVariantCC();
   writable->SetAsVoid();
   return writable.forget();
 }
 
@@ -1891,20 +1827,20 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_
 #ifdef MOZ_WEBSPEECH
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSpeechSynthesis)
 #endif
 
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOuterWindow)
 
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mListenerManager)
 
-  for (nsTimeout* timeout = tmp->mTimeouts.getFirst();
+  for (Timeout* timeout = tmp->mTimeouts.getFirst();
        timeout;
        timeout = timeout->getNext()) {
-    cb.NoteNativeChild(timeout, NS_CYCLE_COLLECTION_PARTICIPANT(nsTimeout));
+    cb.NoteNativeChild(timeout, NS_CYCLE_COLLECTION_PARTICIPANT(Timeout));
   }
 
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mLocation)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mHistory)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCustomElements)
 
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mLocalStorage)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSessionStorage)
@@ -2054,17 +1990,17 @@ nsGlobalWindow::IsBlackForCC(bool aTraci
           IsBlack()) &&
          (!aTracingNeeded ||
           HasNothingToTrace(static_cast<nsIDOMEventTarget*>(this)));
 }
 
 void
 nsGlobalWindow::UnmarkGrayTimers()
 {
-  for (nsTimeout* timeout = mTimeouts.getFirst();
+  for (Timeout* timeout = mTimeouts.getFirst();
        timeout;
        timeout = timeout->getNext()) {
     if (timeout->mScriptHandler) {
       Function* f = timeout->mScriptHandler->GetCallback();
       if (f) {
         f->MarkForCC();
       }
     }
@@ -11700,17 +11636,17 @@ nsGlobalWindow::Suspend()
     for (uint32_t i = 0; i < mEnabledSensors.Length(); i++)
       ac->RemoveWindowListener(mEnabledSensors[i], this);
   }
   DisableGamepadUpdates();
   DisableVRUpdates();
 
   mozilla::dom::workers::SuspendWorkersForWindow(AsInner());
 
-  for (nsTimeout* t = mTimeouts.getFirst(); t; t = t->getNext()) {
+  for (Timeout* t = mTimeouts.getFirst(); t; t = t->getNext()) {
     // Leave the timers with the current time remaining.  This will
     // cause the timers to potentially fire when the window is
     // Resume()'d.  Time effectively passes while suspended.
 
     // Drop the XPCOM timer; we'll reschedule when restoring the state.
     if (t->mTimer) {
       t->mTimer->Cancel();
       t->mTimer = nullptr;
@@ -11759,17 +11695,17 @@ nsGlobalWindow::Resume()
   for (uint32_t i = 0; i < mAudioContexts.Length(); ++i) {
     ErrorResult dummy;
     RefPtr<Promise> d = mAudioContexts[i]->Resume(dummy);
   }
 
   TimeStamp now = TimeStamp::Now();
   DebugOnly<bool> _seenDummyTimeout = false;
 
-  for (nsTimeout* t = mTimeouts.getFirst(); t; t = t->getNext()) {
+  for (Timeout* t = mTimeouts.getFirst(); t; t = t->getNext()) {
     // There's a chance we're being called with RunTimeout on the stack in which
     // case we have a dummy timeout in the list that *must not* be resumed. It
     // can be identified by a null mWindow.
     if (!t->mWindow) {
       NS_ASSERTION(!_seenDummyTimeout, "More than one dummy timeout?!");
       _seenDummyTimeout = true;
       continue;
     }
@@ -11846,17 +11782,17 @@ nsGlobalWindow::FreezeInternal()
   MOZ_ASSERT(mSuspendDepth >= mFreezeDepth);
   if (mFreezeDepth != 1) {
     return;
   }
 
   mozilla::dom::workers::FreezeWorkersForWindow(AsInner());
 
   TimeStamp now = TimeStamp::Now();
-  for (nsTimeout *t = mTimeouts.getFirst(); t; t = t->getNext()) {
+  for (Timeout *t = mTimeouts.getFirst(); t; t = t->getNext()) {
     // Save the current remaining time for this timeout.  We will
     // re-apply it when the window is Thaw()'d.  This effectively
     // shifts timers to the right as if time does not pass while
     // the window is frozen.
     if (t->mWhen > now) {
       t->mTimeRemaining = t->mWhen - now;
     } else {
       t->mTimeRemaining = TimeDuration(0);
@@ -11892,17 +11828,17 @@ nsGlobalWindow::ThawInternal()
   MOZ_ASSERT(mSuspendDepth >= mFreezeDepth);
   if (mFreezeDepth != 0) {
     return;
   }
 
   TimeStamp now = TimeStamp::Now();
   DebugOnly<bool> _seenDummyTimeout = false;
 
-  for (nsTimeout *t = mTimeouts.getFirst(); t; t = t->getNext()) {
+  for (Timeout *t = mTimeouts.getFirst(); t; t = t->getNext()) {
     // There's a chance we're being called with RunTimeout on the stack in which
     // case we have a dummy timeout in the list that *must not* be resumed. It
     // can be identified by a null mWindow.
     if (!t->mWindow) {
       NS_ASSERTION(!_seenDummyTimeout, "More than one dummy timeout?!");
       _seenDummyTimeout = true;
       continue;
     }
@@ -12430,19 +12366,19 @@ nsGlobalWindow::SetInterval(JSContext* a
                             ErrorResult& aError)
 {
   int32_t timeout;
   bool isInterval = IsInterval(aTimeout, timeout);
   return SetTimeoutOrInterval(aCx, aHandler, timeout, isInterval, aError);
 }
 
 nsresult
-nsGlobalWindow::SetTimeoutOrInterval(nsIScriptTimeoutHandler *aHandler,
-                                     int32_t interval,
-                                     bool aIsInterval, int32_t *aReturn)
+nsGlobalWindow::SetTimeoutOrInterval(nsIScriptTimeoutHandler* aHandler,
+                                     int32_t interval, bool aIsInterval,
+                                     int32_t* aReturn)
 {
   MOZ_ASSERT(IsInnerWindow());
 
   // If we don't have a document (we could have been unloaded since
   // the call to setTimeout was made), do nothing.
   if (!mDoc) {
     return NS_OK;
   }
@@ -12454,17 +12390,17 @@ nsGlobalWindow::SetTimeoutOrInterval(nsI
   // Make sure we don't proceed with an interval larger than our timer
   // code can handle. (Note: we already forced |interval| to be non-negative,
   // so the uint32_t cast (to avoid compiler warnings) is ok.)
   uint32_t maxTimeoutMs = PR_IntervalToMilliseconds(DOM_MAX_TIMEOUT_VALUE);
   if (static_cast<uint32_t>(interval) > maxTimeoutMs) {
     interval = maxTimeoutMs;
   }
 
-  RefPtr<nsTimeout> timeout = new nsTimeout();
+  RefPtr<Timeout> timeout = new Timeout();
   timeout->mIsInterval = aIsInterval;
   timeout->mInterval = interval;
   timeout->mScriptHandler = aHandler;
 
   // Now clamp the actual interval we will use for the timer based on
   uint32_t nestingLevel = sNestingLevel + 1;
   uint32_t realInterval = interval;
   if (aIsInterval || nestingLevel >= DOM_CLAMP_TIMEOUT_NESTING_LEVEL) {
@@ -12493,17 +12429,17 @@ nsGlobalWindow::SetTimeoutOrInterval(nsI
     MOZ_ASSERT(!timeout->mWhen.IsNull());
 
     nsresult rv;
     timeout->mTimer = do_CreateInstance("@mozilla.org/timer;1", &rv);
     if (NS_FAILED(rv)) {
       return rv;
     }
 
-    RefPtr<nsTimeout> copy = timeout;
+    RefPtr<Timeout> copy = timeout;
 
     rv = timeout->InitTimer(realInterval);
     if (NS_FAILED(rv)) {
       return rv;
     }
 
     // The timeout is now also held in the timer's closure.
     Unused << copy.forget();
@@ -12536,17 +12472,16 @@ nsGlobalWindow::SetTimeoutOrInterval(nsI
   }
 
   InsertTimeoutIntoList(timeout);
 
   timeout->mPublicId = ++mTimeoutPublicIdCounter;
   *aReturn = timeout->mPublicId;
 
   return NS_OK;
-
 }
 
 int32_t
 nsGlobalWindow::SetTimeoutOrInterval(JSContext *aCx, Function& aFunction,
                                      int32_t aTimeout,
                                      const Sequence<JS::Value>& aArguments,
                                      bool aIsInterval, ErrorResult& aError)
 {
@@ -12593,23 +12528,23 @@ nsGlobalWindow::SetTimeoutOrInterval(JSC
   }
 
   int32_t result;
   aError = SetTimeoutOrInterval(handler, aTimeout, aIsInterval, &result);
   return result;
 }
 
 bool
-nsGlobalWindow::RunTimeoutHandler(nsTimeout* aTimeout,
+nsGlobalWindow::RunTimeoutHandler(Timeout* aTimeout,
                                   nsIScriptContext* aScx)
 {
   // Hold on to the timeout in case mExpr or mFunObj releases its
   // doc.
-  RefPtr<nsTimeout> timeout = aTimeout;
-  nsTimeout* last_running_timeout = mRunningTimeout;
+  RefPtr<Timeout> timeout = aTimeout;
+  Timeout* last_running_timeout = mRunningTimeout;
   mRunningTimeout = timeout;
   timeout->mRunning = true;
 
   // Push this timeout's popup control state, which should only be
   // eabled the first time a timeout fires that was created while
   // popups were enabled and with a delay less than
   // "dom.disable_open_click_delay".
   nsAutoPopupStatePusher popupStatePusher(timeout->mPopupState);
@@ -12633,16 +12568,17 @@ nsGlobalWindow::RunTimeoutHandler(nsTime
     reason = "setInterval handler";
   } else {
     reason = "setTimeout handler";
   }
 
   bool abortIntervalHandler = false;
   nsCOMPtr<nsIScriptTimeoutHandler> handler(timeout->mScriptHandler);
   RefPtr<Function> callback = handler->GetCallback();
+
   if (!callback) {
     // Evaluate the timeout expression.
     const nsAString& script = handler->GetHandlerText();
 
     const char* filename = nullptr;
     uint32_t lineNo = 0, dummyColumn = 0;
     handler->GetLocation(&filename, &lineNo, &dummyColumn);
 
@@ -12705,17 +12641,17 @@ nsGlobalWindow::RunTimeoutHandler(nsTime
 
   mRunningTimeout = last_running_timeout;
   timeout->mRunning = false;
 
   return timeout->mCleared;
 }
 
 bool
-nsGlobalWindow::RescheduleTimeout(nsTimeout* aTimeout, const TimeStamp& now,
+nsGlobalWindow::RescheduleTimeout(Timeout* aTimeout, const TimeStamp& now,
                                   bool aRunningPendingTimeouts)
 {
   if (!aTimeout->mIsInterval) {
     if (aTimeout->mTimer) {
       // The timeout still has an OS timer, and it's not an interval,
       // that means that the OS timer could still fire; cancel the OS
       // timer and release its reference to the timeout.
       aTimeout->mTimer->Cancel();
@@ -12784,27 +12720,28 @@ nsGlobalWindow::RescheduleTimeout(nsTime
 
     return false;
   }
 
   return true;
 }
 
 void
-nsGlobalWindow::RunTimeout(nsTimeout *aTimeout)
+nsGlobalWindow::RunTimeout(Timeout* aTimeout)
 {
   if (IsSuspended()) {
     return;
   }
 
   NS_ASSERTION(IsInnerWindow(), "Timeout running on outer window!");
   NS_ASSERTION(!IsFrozen(), "Timeout running on a window in the bfcache!");
 
-  nsTimeout *nextTimeout;
-  nsTimeout *last_expired_timeout, *last_insertion_point;
+  Timeout* nextTimeout;
+  Timeout* last_expired_timeout;
+  Timeout* last_insertion_point;
   uint32_t firingDepth = mTimeoutFiringDepth + 1;
 
   // Make sure that the window and the script context don't go away as
   // a result of running timeouts
   nsCOMPtr<nsIScriptGlobalObject> windowKungFuDeathGrip(this);
 
   // A native timer has gone off. See which of our timeouts need
   // servicing
@@ -12825,17 +12762,17 @@ nsGlobalWindow::RunTimeout(nsTimeout *aT
 
   // The timeout list is kept in deadline order. Discover the latest timeout
   // whose deadline has expired. On some platforms, native timeout events fire
   // "early", but we handled that above by setting deadline to aTimeout->mWhen
   // if the timer fired early.  So we can stop walking if we get to timeouts
   // whose mWhen is greater than deadline, since once that happens we know
   // nothing past that point is expired.
   last_expired_timeout = nullptr;
-  for (nsTimeout *timeout = mTimeouts.getFirst();
+  for (Timeout* timeout = mTimeouts.getFirst();
        timeout && timeout->mWhen <= deadline;
        timeout = timeout->getNext()) {
     if (timeout->mFiringDepth == 0) {
       // Mark any timeouts that are on the list to be fired with the
       // firing depth so that we can reentrantly run timeouts
       timeout->mFiringDepth = firingDepth;
       last_expired_timeout = timeout;
     }
@@ -12855,28 +12792,28 @@ nsGlobalWindow::RunTimeout(nsTimeout *aT
     gLastRecordedRecentTimeouts = now;
   }
 
   // Insert a dummy timeout into the list of timeouts between the
   // portion of the list that we are about to process now and those
   // timeouts that will be processed in a future call to
   // win_run_timeout(). This dummy timeout serves as the head of the
   // list for any timeouts inserted as a result of running a timeout.
-  RefPtr<nsTimeout> dummy_timeout = new nsTimeout();
+  RefPtr<Timeout> dummy_timeout = new Timeout();
   dummy_timeout->mFiringDepth = firingDepth;
   dummy_timeout->mWhen = now;
   last_expired_timeout->setNext(dummy_timeout);
-  RefPtr<nsTimeout> timeoutExtraRef(dummy_timeout);
+  RefPtr<Timeout> timeoutExtraRef(dummy_timeout);
 
   last_insertion_point = mTimeoutInsertionPoint;
   // If we ever start setting mTimeoutInsertionPoint to a non-dummy timeout,
   // the logic in ResetTimersForNonBackgroundWindow will need to change.
   mTimeoutInsertionPoint = dummy_timeout;
 
-  for (nsTimeout *timeout = mTimeouts.getFirst();
+  for (Timeout* timeout = mTimeouts.getFirst();
        timeout != dummy_timeout && !IsFrozen();
        timeout = nextTimeout) {
     nextTimeout = timeout->getNext();
 
     if (timeout->mFiringDepth != firingDepth) {
       // We skip the timeout since it's on the list to run at another
       // depth.
 
@@ -12943,25 +12880,25 @@ nsGlobalWindow::RunTimeout(nsTimeout *aT
   dummy_timeout->remove();
   timeoutExtraRef = nullptr;
   MOZ_ASSERT(dummy_timeout->HasRefCntOne(), "dummy_timeout may leak");
 
   mTimeoutInsertionPoint = last_insertion_point;
 }
 
 void
-nsGlobalWindow::ClearTimeoutOrInterval(int32_t aTimerID)
+nsGlobalWindow::ClearTimeoutOrInterval(int32_t aTimerId)
 {
   MOZ_RELEASE_ASSERT(IsInnerWindow());
 
-  uint32_t public_id = (uint32_t)aTimerID;
-  nsTimeout *timeout;
+  uint32_t timerId = (uint32_t)aTimerId;
+  Timeout* timeout;
 
   for (timeout = mTimeouts.getFirst(); timeout; timeout = timeout->getNext()) {
-    if (timeout->mPublicId == public_id) {
+    if (timeout->mPublicId == timerId) {
       if (timeout->mRunning) {
         /* We're running from inside the timeout. Mark this
            timeout for deferred deletion by the code in
            RunTimeout() */
         timeout->mIsInterval = false;
       }
       else {
         /* Delete the timeout from the pending timeout list */
@@ -12992,17 +12929,17 @@ nsresult nsGlobalWindow::ResetTimersForN
 
   // If mTimeoutInsertionPoint is non-null, we're in the middle of firing
   // timers and the timers we're planning to fire all come before
   // mTimeoutInsertionPoint; mTimeoutInsertionPoint itself is a dummy timeout
   // with an mWhen that may be semi-bogus.  In that case, we don't need to do
   // anything with mTimeoutInsertionPoint or anything before it, so should
   // start at the timer after mTimeoutInsertionPoint, if there is one.
   // Otherwise, start at the beginning of the list.
-  for (nsTimeout *timeout = mTimeoutInsertionPoint ?
+  for (Timeout* timeout = mTimeoutInsertionPoint ?
          mTimeoutInsertionPoint->getNext() : mTimeouts.getFirst();
        timeout; ) {
     // It's important that this check be <= so that we guarantee that
     // taking std::max with |now| won't make a quantity equal to
     // timeout->mWhen below.
     if (timeout->mWhen <= now) {
       timeout = timeout->getNext();
       continue;
@@ -13036,17 +12973,17 @@ nsresult nsGlobalWindow::ResetTimersForN
       TimeDuration delay = firingTime - now;
       timeout->mWhen = firingTime;
 
       // Since we reset mWhen we need to move |timeout| to the right
       // place in the list so that it remains sorted by mWhen.
 
       // Get the pointer to the next timeout now, before we move the
       // current timeout in the list.
-      nsTimeout* nextTimeout = timeout->getNext();
+      Timeout* nextTimeout = timeout->getNext();
 
       // It is safe to remove and re-insert because mWhen is now
       // strictly smaller than it used to be, so we know we'll insert
       // |timeout| before nextTimeout.
       NS_ASSERTION(!nextTimeout ||
                    timeout->mWhen < nextTimeout->mWhen, "How did that happen?");
       timeout->remove();
       // InsertTimeoutIntoList will addref |timeout| and reset
@@ -13070,17 +13007,18 @@ nsresult nsGlobalWindow::ResetTimersForN
   }
 
   return NS_OK;
 }
 
 void
 nsGlobalWindow::ClearAllTimeouts()
 {
-  nsTimeout *timeout, *nextTimeout;
+  Timeout* timeout;
+  Timeout* nextTimeout;
 
   for (timeout = mTimeouts.getFirst(); timeout; timeout = nextTimeout) {
     /* If RunTimeout() is higher up on the stack for this
        window, e.g. as a result of document.write from a timeout,
        then we need to reset the list insertion point for
        newly-created timeouts in case the user adds a timeout,
        before we pop the stack back to RunTimeout. */
     if (mRunningTimeout == timeout)
@@ -13105,25 +13043,25 @@ nsGlobalWindow::ClearAllTimeouts()
     timeout->Release();
   }
 
   // Clear out our list
   mTimeouts.clear();
 }
 
 void
-nsGlobalWindow::InsertTimeoutIntoList(nsTimeout *aTimeout)
+nsGlobalWindow::InsertTimeoutIntoList(Timeout* aTimeout)
 {
   NS_ASSERTION(IsInnerWindow(),
                "InsertTimeoutIntoList() called on outer window!");
 
   // Start at mLastTimeout and go backwards.  Don't go further than
   // mTimeoutInsertionPoint, though.  This optimizes for the common case of
   // insertion at the end.
-  nsTimeout* prevSibling;
+  Timeout* prevSibling;
   for (prevSibling = mTimeouts.getLast();
        prevSibling && prevSibling != mTimeoutInsertionPoint &&
          // This condition needs to match the one in SetTimeoutOrInterval that
          // determines whether to set mWhen or mTimeRemaining.
          (IsFrozen() ?
           prevSibling->mTimeRemaining > aTimeout->mTimeRemaining :
           prevSibling->mWhen > aTimeout->mWhen);
        prevSibling = prevSibling->getPrevious()) {
@@ -13143,34 +13081,21 @@ nsGlobalWindow::InsertTimeoutIntoList(ns
   // by the list
   aTimeout->AddRef();
 }
 
 // static
 void
 nsGlobalWindow::TimerCallback(nsITimer *aTimer, void *aClosure)
 {
-  RefPtr<nsTimeout> timeout = (nsTimeout *)aClosure;
+  RefPtr<Timeout> timeout = (Timeout*)aClosure;
 
   timeout->mWindow->RunTimeout(timeout);
 }
 
-// static
-void
-nsGlobalWindow::TimerNameCallback(nsITimer* aTimer, void* aClosure, char* aBuf,
-                                  size_t aLen)
-{
-  RefPtr<nsTimeout> timeout = (nsTimeout*)aClosure;
-
-  const char* filename;
-  uint32_t lineNum, column;
-  timeout->mScriptHandler->GetLocation(&filename, &lineNum, &column);
-  snprintf(aBuf, aLen, "[content] %s:%u:%u", filename, lineNum, column);
-}
-
 //*****************************************************************************
 // nsGlobalWindow: Helper Functions
 //*****************************************************************************
 
 already_AddRefed<nsIDocShellTreeOwner>
 nsGlobalWindow::GetTreeOwner()
 {
   FORWARD_TO_OUTER(GetTreeOwner, (), nullptr);

--- a/dom/base/nsGlobalWindow.h
+++ b/dom/base/nsGlobalWindow.h
@@ -51,16 +51,17 @@
 #include "nsIDocument.h"
 #include "mozilla/dom/EventTarget.h"
 #include "mozilla/dom/WindowBinding.h"
 #include "Units.h"
 #include "nsComponentManagerUtils.h"
 #include "nsSize.h"
 #include "nsCheapSets.h"
 #include "mozilla/dom/ImageBitmapSource.h"
+#include "mozilla/dom/Timeout.h"
 
 #define DEFAULT_HOME_PAGE "www.mozilla.org"
 #define PREF_BROWSER_STARTUP_HOMEPAGE "browser.startup.homepage"
 
 // Amount of time allowed between alert/prompt/confirm before enabling
 // the stop dialog checkbox.
 #define DEFAULT_SUCCESSIVE_DIALOG_TIME_LIMIT 3 // 3 sec
 
@@ -119,16 +120,17 @@ class Navigator;
 class OwningExternalOrWindowProxy;
 class Promise;
 class PostMessageEvent;
 struct RequestInit;
 class RequestOrUSVString;
 class Selection;
 class SpeechSynthesis;
 class TabGroup;
+class Timeout;
 class U2F;
 class VRDisplay;
 class VREventObserver;
 class WakeLock;
 #if defined(MOZ_WIDGET_ANDROID) || defined(MOZ_WIDGET_GONK)
 class WindowOrientationObserver;
 #endif
 namespace cache {
@@ -146,79 +148,16 @@ NS_CreateJSTimeoutHandler(JSContext* aCx
 
 extern already_AddRefed<nsIScriptTimeoutHandler>
 NS_CreateJSTimeoutHandler(JSContext* aCx, nsGlobalWindow *aWindow,
                           const nsAString& aExpression,
                           mozilla::ErrorResult& aError);
 
 extern const js::Class OuterWindowProxyClass;
 
-/*
- * Timeout struct that holds information about each script
- * timeout.  Holds a strong reference to an nsIScriptTimeoutHandler, which
- * abstracts the language specific cruft.
- */
-struct nsTimeout final
-  : mozilla::LinkedListElement<nsTimeout>
-{
-private:
-  ~nsTimeout();
-
-public:
-  nsTimeout();
-
-  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(nsTimeout)
-  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(nsTimeout)
-
-  nsresult InitTimer(uint32_t aDelay);
-
-  bool HasRefCntOne();
-
-  // Window for which this timeout fires
-  RefPtr<nsGlobalWindow> mWindow;
-
-  // The actual timer object
-  nsCOMPtr<nsITimer> mTimer;
-
-  // True if the timeout was cleared
-  bool mCleared;
-
-  // True if this is one of the timeouts that are currently running
-  bool mRunning;
-
-  // True if this is a repeating/interval timer
-  bool mIsInterval;
-
-  // Returned as value of setTimeout()
-  uint32_t mPublicId;
-
-  // Interval in milliseconds
-  uint32_t mInterval;
-
-  // mWhen and mTimeRemaining can't be in a union, sadly, because they
-  // have constructors.
-  // Nominal time to run this timeout.  Use only when timeouts are not
-  // suspended.
-  mozilla::TimeStamp mWhen;
-  // Remaining time to wait.  Used only when timeouts are suspended.
-  mozilla::TimeDuration mTimeRemaining;
-
-  // stack depth at which timeout is firing
-  uint32_t mFiringDepth;
-
-  uint32_t mNestingLevel;
-
-  // The popup state at timeout creation time if not created from
-  // another timeout
-  PopupControlState mPopupState;
-
-  // The language-specific information about the callback.
-  nsCOMPtr<nsIScriptTimeoutHandler> mScriptHandler;
-};
-
 struct IdleObserverHolder
 {
   nsCOMPtr<nsIIdleObserver> mIdleObserver;
   uint32_t mTimeInS;
   bool mPrevNotificationIdle;
 
   IdleObserverHolder()
     : mTimeInS(0), mPrevNotificationIdle(false)
@@ -1504,48 +1443,46 @@ private:
 
   void FreezeInternal();
   void ThawInternal();
 
 public:
   // Timeout Functions
   // Language agnostic timeout function (all args passed).
   // |interval| is in milliseconds.
-  nsresult SetTimeoutOrInterval(nsIScriptTimeoutHandler *aHandler,
-                                int32_t interval,
-                                bool aIsInterval, int32_t* aReturn);
+  nsresult SetTimeoutOrInterval(nsIScriptTimeoutHandler* aHandler,
+                                int32_t interval, bool aIsInterval,
+                                int32_t* aReturn);
   int32_t SetTimeoutOrInterval(JSContext* aCx,
                                mozilla::dom::Function& aFunction,
                                int32_t aTimeout,
                                const mozilla::dom::Sequence<JS::Value>& aArguments,
                                bool aIsInterval, mozilla::ErrorResult& aError);
   int32_t SetTimeoutOrInterval(JSContext* aCx, const nsAString& aHandler,
                                int32_t aTimeout, bool aIsInterval,
                                mozilla::ErrorResult& aError);
-  void ClearTimeoutOrInterval(int32_t aTimerID);
+  void ClearTimeoutOrInterval(int32_t aTimerId);
 
   // JS specific timeout functions (JS args grabbed from context).
   nsresult ResetTimersForNonBackgroundWindow();
 
   // The timeout implementation functions.
-  void RunTimeout(nsTimeout *aTimeout);
+  void RunTimeout(mozilla::dom::Timeout* aTimeout);
   void RunTimeout() { RunTimeout(nullptr); }
   // Return true if |aTimeout| was cleared while its handler ran.
-  bool RunTimeoutHandler(nsTimeout* aTimeout, nsIScriptContext* aScx);
+  bool RunTimeoutHandler(mozilla::dom::Timeout* aTimeout, nsIScriptContext* aScx);
   // Return true if |aTimeout| needs to be reinserted into the timeout list.
-  bool RescheduleTimeout(nsTimeout* aTimeout, const TimeStamp& now,
+  bool RescheduleTimeout(mozilla::dom::Timeout* aTimeout, const TimeStamp& now,
                          bool aRunningPendingTimeouts);
 
   void ClearAllTimeouts();
   // Insert aTimeout into the list, before all timeouts that would
   // fire after it, but no earlier than mTimeoutInsertionPoint, if any.
-  void InsertTimeoutIntoList(nsTimeout *aTimeout);
+  void InsertTimeoutIntoList(mozilla::dom::Timeout* aTimeout);
   static void TimerCallback(nsITimer *aTimer, void *aClosure);
-  static void TimerNameCallback(nsITimer* aTimer, void* aClosure, char* aBuf,
-                                size_t aLen);
 
   // Helper Functions
   already_AddRefed<nsIDocShellTreeOwner> GetTreeOwner();
   already_AddRefed<nsIBaseWindow> GetTreeOwnerWindow();
   already_AddRefed<nsIWebBrowserChrome> GetWebBrowserChrome();
   nsresult SecurityCheckURL(const char *aURL);
   bool IsPrivateBrowsing();
 
@@ -1844,17 +1781,17 @@ protected:
   RefPtr<nsDOMWindowList>     mFrames;
   // All BarProps are inner window only.
   RefPtr<mozilla::dom::BarProp> mMenubar;
   RefPtr<mozilla::dom::BarProp> mToolbar;
   RefPtr<mozilla::dom::BarProp> mLocationbar;
   RefPtr<mozilla::dom::BarProp> mPersonalbar;
   RefPtr<mozilla::dom::BarProp> mStatusbar;
   RefPtr<mozilla::dom::BarProp> mScrollbars;
-  RefPtr<nsDOMWindowUtils>    mWindowUtils;
+  RefPtr<nsDOMWindowUtils>      mWindowUtils;
   nsString                      mStatus;
   nsString                      mDefaultStatus;
   RefPtr<nsGlobalWindowObserver> mObserver; // Inner windows only.
   RefPtr<mozilla::dom::Crypto>  mCrypto;
   RefPtr<mozilla::dom::U2F> mU2F;
   RefPtr<mozilla::dom::cache::CacheStorage> mCacheStorage;
   RefPtr<mozilla::dom::Console> mConsole;
   // We need to store an nsISupports pointer to this object because the
@@ -1869,23 +1806,23 @@ protected:
   RefPtr<mozilla::dom::DOMStorage> mSessionStorage;
 
   // These member variable are used only on inner windows.
   RefPtr<mozilla::EventListenerManager> mListenerManager;
   // mTimeouts is generally sorted by mWhen, unless mTimeoutInsertionPoint is
   // non-null.  In that case, the dummy timeout pointed to by
   // mTimeoutInsertionPoint may have a later mWhen than some of the timeouts
   // that come after it.
-  mozilla::LinkedList<nsTimeout> mTimeouts;
+  mozilla::LinkedList<mozilla::dom::Timeout> mTimeouts;
   // If mTimeoutInsertionPoint is non-null, insertions should happen after it.
   // This is a dummy timeout at the moment; if that ever changes, the logic in
   // ResetTimersForNonBackgroundWindow needs to change.
-  nsTimeout*                    mTimeoutInsertionPoint;
-  uint32_t                      mTimeoutPublicIdCounter;
-  uint32_t                      mTimeoutFiringDepth;
+  mozilla::dom::Timeout*      mTimeoutInsertionPoint;
+  uint32_t                    mTimeoutPublicIdCounter;
+  uint32_t                    mTimeoutFiringDepth;
   RefPtr<mozilla::dom::Location> mLocation;
   RefPtr<nsHistory>           mHistory;
   RefPtr<mozilla::dom::CustomElementRegistry> mCustomElements;
 
   // These member variables are used on both inner and the outer windows.
   nsCOMPtr<nsIPrincipal> mDocumentPrincipal;
 
   typedef nsTArray<RefPtr<mozilla::dom::StorageEvent>> nsDOMStorageEventArray;

--- a/dom/base/nsIScriptTimeoutHandler.h
+++ b/dom/base/nsIScriptTimeoutHandler.h
@@ -3,16 +3,18 @@
 /* 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 nsIScriptTimeoutHandler_h___
 #define nsIScriptTimeoutHandler_h___
 
 #include "nsTArray.h"
 #include "js/TypeDecls.h"
+#include "mozilla/Function.h"
+#include "mozilla/Maybe.h"
 
 namespace mozilla {
 namespace dom {
 class Function;
 } // namespace dom
 } // namespace mozilla
 
 #define NS_ISCRIPTTIMEOUTHANDLER_IID \
@@ -26,17 +28,17 @@ class Function;
 
 class nsIScriptTimeoutHandler : public nsISupports
 {
 public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ISCRIPTTIMEOUTHANDLER_IID)
 
   // Get the Function to call.  If this returns nullptr, GetHandlerText() will
   // be called to get the string.
-  virtual mozilla::dom::Function *GetCallback() = 0;
+  virtual mozilla::dom::Function* GetCallback() = 0;
 
   // Get the handler text of not a compiled object.
   virtual const nsAString& GetHandlerText() = 0;
 
   // Get the location of the script.
   // Note: The memory pointed to by aFileName is owned by the
   // nsIScriptTimeoutHandler and should not be freed by the caller.
   virtual void GetLocation(const char **aFileName, uint32_t *aLineNo,

--- a/dom/base/nsJSTimeoutHandler.cpp
+++ b/dom/base/nsJSTimeoutHandler.cpp
@@ -1,29 +1,32 @@
 /* -*- 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/. */
 
+#include <algorithm>
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Function.h"
+#include "mozilla/Likely.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/dom/FunctionBinding.h"
+#include "nsAXPCNativeCallContext.h"
 #include "nsCOMPtr.h"
+#include "nsContentUtils.h"
+#include "nsError.h"
+#include "nsGlobalWindow.h"
+#include "nsIContentSecurityPolicy.h"
 #include "nsIDocument.h"
 #include "nsIScriptTimeoutHandler.h"
 #include "nsIXPConnect.h"
 #include "nsJSUtils.h"
-#include "nsContentUtils.h"
-#include "nsError.h"
-#include "nsGlobalWindow.h"
-#include "nsIContentSecurityPolicy.h"
-#include "mozilla/Attributes.h"
-#include "mozilla/Likely.h"
-#include <algorithm>
-#include "mozilla/dom/FunctionBinding.h"
 #include "WorkerPrivate.h"
-#include "nsAXPCNativeCallContext.h"
 
 static const char kSetIntervalStr[] = "setInterval";
 static const char kSetTimeoutStr[] = "setTimeout";
 
 using namespace mozilla;
 using namespace mozilla::dom;
 using namespace mozilla::dom::workers;
 
@@ -32,34 +35,36 @@ class nsJSScriptTimeoutHandler final : p
 {
 public:
   // nsISupports
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(nsJSScriptTimeoutHandler)
 
   nsJSScriptTimeoutHandler();
   // This will call SwapElements on aArguments with an empty array.
-  nsJSScriptTimeoutHandler(JSContext* aCx, nsGlobalWindow *aWindow,
+  nsJSScriptTimeoutHandler(JSContext* aCx, nsGlobalWindow* aWindow,
                            Function& aFunction,
                            nsTArray<JS::Heap<JS::Value>>&& aArguments,
                            ErrorResult& aError);
-  nsJSScriptTimeoutHandler(JSContext* aCx, nsGlobalWindow *aWindow,
+  nsJSScriptTimeoutHandler(JSContext* aCx, nsGlobalWindow* aWindow,
                            const nsAString& aExpression, bool* aAllowEval,
                            ErrorResult& aError);
   nsJSScriptTimeoutHandler(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
                            Function& aFunction,
                            nsTArray<JS::Heap<JS::Value>>&& aArguments);
   nsJSScriptTimeoutHandler(JSContext* aCx, WorkerPrivate* aWorkerPrivate,
                            const nsAString& aExpression);
 
   virtual const nsAString& GetHandlerText() override;
+
   virtual Function* GetCallback() override
   {
     return mFunction;
   }
+
   virtual void GetLocation(const char** aFileName, uint32_t* aLineNo,
                            uint32_t* aColumn) override
   {
     *aFileName = mFileName.get();
     *aLineNo = mLineNo;
     *aColumn = mColumn;
   }
 

--- a/dom/base/nsPIDOMWindow.h
+++ b/dom/base/nsPIDOMWindow.h
@@ -31,26 +31,26 @@ class nsIDocument;
 class nsIIdleObserver;
 class nsIPrincipal;
 class nsIScriptTimeoutHandler;
 class nsIURI;
 class nsPIDOMWindowInner;
 class nsPIDOMWindowOuter;
 class nsPIWindowRoot;
 class nsXBLPrototypeHandler;
-struct nsTimeout;
 
 typedef uint32_t SuspendTypes;
 
 namespace mozilla {
 namespace dom {
 class AudioContext;
 class Element;
 class Performance;
 class ServiceWorkerRegistration;
+class Timeout;
 class CustomElementRegistry;
 } // namespace dom
 } // namespace mozilla
 
 // Popup control state enum. The values in this enum must go from most
 // permissive to least permissive so that it's safe to push state in
 // all situations. Pushing popup state onto the stack never makes the
 // current popup state less permissive (see
@@ -616,17 +616,17 @@ protected:
   typedef nsRefPtrHashtable<nsStringHashKey,
                             mozilla::dom::ServiceWorkerRegistration>
           ServiceWorkerRegistrationTable;
   ServiceWorkerRegistrationTable mServiceWorkerRegistrationTable;
 
   uint32_t               mModalStateDepth;
 
   // These variables are only used on inner windows.
-  nsTimeout             *mRunningTimeout;
+  mozilla::dom::Timeout *mRunningTimeout;
 
   uint32_t               mMutationBits;
 
   bool                   mIsDocumentLoaded;
   bool                   mIsHandlingResizeEvent;
   bool                   mIsInnerWindow;
   bool                   mMayHavePaintEventListener;
   bool                   mMayHaveTouchEventListener;