--- a/caps/nsScriptSecurityManager.cpp
+++ b/caps/nsScriptSecurityManager.cpp
@@ -1436,17 +1436,17 @@ nsScriptSecurityManager::InitStatics()
 
 // Currently this nsGenericFactory constructor is used only from FastLoad
 // (XPCOM object deserialization) code, when "creating" the system principal
 // singleton.
 already_AddRefed<SystemPrincipal>
 nsScriptSecurityManager::SystemPrincipalSingletonConstructor()
 {
     if (gScriptSecMan)
-        return do_AddRef(gScriptSecMan->mSystemPrincipal.get()).downcast<SystemPrincipal>();
+        return do_AddRef(gScriptSecMan->mSystemPrincipal).downcast<SystemPrincipal>();
     return nullptr;
 }
 
 struct IsWhitespace {
     static bool Test(char aChar) { return NS_IsAsciiWhitespace(aChar); };
 };
 struct IsWhitespaceOrComma {
     static bool Test(char aChar) { return aChar == ',' || NS_IsAsciiWhitespace(aChar); };

--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -2491,17 +2491,17 @@ nsDocument::MaybeDowngradePrincipal(nsIP
   // automatically downgrade it to the last principal it subsumes (which is the
   // extension principal, in the case of extension content scripts).
   auto* basePrin = BasePrincipal::Cast(aPrincipal);
   if (basePrin->Is<ExpandedPrincipal>()) {
     auto* expanded = basePrin->As<ExpandedPrincipal>();
 
     MOZ_ASSERT(expanded->WhiteList().Length() > 0);
 
-    return do_AddRef(expanded->WhiteList().LastElement().get());
+    return do_AddRef(expanded->WhiteList().LastElement());
   }
 
   if (!sChromeInContentPrefCached) {
     sChromeInContentPrefCached = true;
     Preferences::AddBoolVarCache(&sChromeInContentAllowed,
                                  kChromeInContentPref, false);
   }
   if (!sChromeInContentAllowed &&

--- a/gfx/src/nsDeviceContext.cpp
+++ b/gfx/src/nsDeviceContext.cpp
@@ -139,17 +139,17 @@ nsFontCache::GetMetricsFor(const nsFont&
 
     // It's not in the cache. Get font metrics and then cache them.
 
     nsFontMetrics::Params params = aParams;
     params.language = language;
     RefPtr<nsFontMetrics> fm = new nsFontMetrics(aFont, params, mContext);
     // the mFontMetrics list has the "head" at the end, because append
     // is cheaper than insert
-    mFontMetrics.AppendElement(do_AddRef(fm.get()).take());
+    mFontMetrics.AppendElement(do_AddRef(fm).take());
     return fm.forget();
 }
 
 void
 nsFontCache::UpdateUserFonts(gfxUserFontSet* aUserFontSet)
 {
     for (nsFontMetrics* fm : mFontMetrics) {
         gfxFontGroup* fg = fm->GetThebesFontGroup();

--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -12292,17 +12292,17 @@ nsCSSFrameConstructor::CreateListBoxCont
   if (nullptr != aParentFrame) {
     nsFrameItems            frameItems;
     TreeMatchContextHolder matchContext(mDocument);
     nsFrameConstructorState state(mPresShell,
                                   matchContext,
                                   GetAbsoluteContainingBlock(aParentFrame, FIXED_POS),
                                   GetAbsoluteContainingBlock(aParentFrame, ABS_POS),
                                   GetFloatContainingBlock(aParentFrame),
-                                  do_AddRef(mTempFrameTreeState.get()));
+                                  do_AddRef(mTempFrameTreeState));
 
     // If we ever initialize the ancestor filter on |state|, make sure
     // to push the right parent!
 
     RefPtr<nsStyleContext> styleContext;
     styleContext = ResolveStyleContext(aParentFrame, aChild, &state);
 
     // Pre-check for display "none" - only if we find that, do we create

--- a/layout/base/nsPresContext.cpp
+++ b/layout/base/nsPresContext.cpp
@@ -3486,17 +3486,17 @@ nsRootPresContext::CancelAllDidPaintTime
 }
 
 void
 nsRootPresContext::AddWillPaintObserver(nsIRunnable* aRunnable)
 {
   if (!mWillPaintFallbackEvent.IsPending()) {
     mWillPaintFallbackEvent = new RunWillPaintObservers(this);
     Document()->Dispatch(TaskCategory::Other,
-                         do_AddRef(mWillPaintFallbackEvent.get()));
+                         do_AddRef(mWillPaintFallbackEvent));
   }
   mWillPaintObservers.AppendElement(aRunnable);
 }
 
 /**
  * Run all runnables that need to get called before the next paint.
  */
 void

--- a/netwerk/protocol/res/ExtensionProtocolHandler.cpp
+++ b/netwerk/protocol/res/ExtensionProtocolHandler.cpp
@@ -333,17 +333,17 @@ NS_IMPL_RELEASE_INHERITED(ExtensionProto
 
 already_AddRefed<ExtensionProtocolHandler>
 ExtensionProtocolHandler::GetSingleton()
 {
   if (!sSingleton) {
     sSingleton = new ExtensionProtocolHandler();
     ClearOnShutdown(&sSingleton);
   }
-  return do_AddRef(sSingleton.get());
+  return do_AddRef(sSingleton);
 }
 
 ExtensionProtocolHandler::ExtensionProtocolHandler()
   : SubstitutingProtocolHandler(EXTENSION_SCHEME)
 #if !defined(XP_WIN)
 #if defined(XP_MACOSX)
   , mAlreadyCheckedDevRepo(false)
 #endif /* XP_MACOSX */

--- a/toolkit/components/extensions/webrequest/StreamFilterParent.cpp
+++ b/toolkit/components/extensions/webrequest/StreamFilterParent.cpp
@@ -40,17 +40,17 @@ class ChannelEventWrapper : public Chann
 {
 public:
   ChannelEventWrapper(nsIEventTarget* aTarget)
     : mTarget(aTarget)
   {}
 
   already_AddRefed<nsIEventTarget> GetEventTarget() override
   {
-    return do_AddRef(mTarget.get());
+    return do_AddRef(mTarget);
   }
 
 protected:
   ~ChannelEventWrapper() override = default;
 
 private:
   nsCOMPtr<nsIEventTarget> mTarget;
 };

--- a/xpcom/base/nsCOMPtr.h
+++ b/xpcom/base/nsCOMPtr.h
@@ -1544,9 +1544,17 @@ RefPtr<T>::operator=(const nsCOMPtr_help
   void* newRawPtr;
   if (NS_FAILED(aHelper(NS_GET_TEMPLATE_IID(T), &newRawPtr))) {
     newRawPtr = nullptr;
   }
   assign_assuming_AddRef(static_cast<T*>(newRawPtr));
   return *this;
 }
 
+template <class T>
+inline already_AddRefed<T>
+do_AddRef(const nsCOMPtr<T>& aObj)
+{
+  nsCOMPtr<T> ref(aObj);
+  return ref.forget();
+}
+
 #endif // !defined(nsCOMPtr_h___)

--- a/xpcom/threads/Scheduler.cpp
+++ b/xpcom/threads/Scheduler.cpp
@@ -322,24 +322,24 @@ SchedulerEventQueue::SetScheduler(Schedu
   MutexAutoLock lock(mLock);
   mScheduler = aScheduler;
 }
 
 already_AddRefed<nsIThreadObserver>
 SchedulerEventQueue::GetObserver()
 {
   MutexAutoLock lock(mLock);
-  return do_AddRef(mObserver.get());
+  return do_AddRef(mObserver);
 }
 
 already_AddRefed<nsIThreadObserver>
 SchedulerEventQueue::GetObserverOnThread()
 {
   MOZ_ASSERT(NS_IsMainThread());
-  return do_AddRef(mObserver.get());
+  return do_AddRef(mObserver);
 }
 
 void
 SchedulerEventQueue::SetObserver(nsIThreadObserver* aObserver)
 {
   MutexAutoLock lock(mLock);
   mObserver = aObserver;
 }

--- a/xpcom/threads/ThreadEventQueue.cpp
+++ b/xpcom/threads/ThreadEventQueue.cpp
@@ -244,24 +244,24 @@ ThreadEventQueue<InnerQueueT>::PopEventQ
   mNestedQueues.RemoveElementAt(mNestedQueues.Length() - 1);
 }
 
 template<class InnerQueueT>
 already_AddRefed<nsIThreadObserver>
 ThreadEventQueue<InnerQueueT>::GetObserver()
 {
   MutexAutoLock lock(mLock);
-  return do_AddRef(mObserver.get());
+  return do_AddRef(mObserver);
 }
 
 template<class InnerQueueT>
 already_AddRefed<nsIThreadObserver>
 ThreadEventQueue<InnerQueueT>::GetObserverOnThread()
 {
-  return do_AddRef(mObserver.get());
+  return do_AddRef(mObserver);
 }
 
 template<class InnerQueueT>
 void
 ThreadEventQueue<InnerQueueT>::SetObserver(nsIThreadObserver* aObserver)
 {
   MutexAutoLock lock(mLock);
   mObserver = aObserver;

--- a/xpcom/threads/nsThreadUtils.h
+++ b/xpcom/threads/nsThreadUtils.h
@@ -1627,16 +1627,23 @@ public:
 private:
   // Not implemented
   nsRevocableEventPtr(const nsRevocableEventPtr&);
   nsRevocableEventPtr& operator=(const nsRevocableEventPtr&);
 
   RefPtr<T> mEvent;
 };
 
+template <class T>
+inline already_AddRefed<T>
+do_AddRef(nsRevocableEventPtr<T>& aObj)
+{
+  return do_AddRef(aObj.get());
+}
+
 /**
  * A simple helper to suffix thread pool name
  * with incremental numbers.
  */
 class nsThreadPoolNaming
 {
 public:
   nsThreadPoolNaming() : mCounter(0) {}