diff --git a/ipc/mscom/Interceptor.cpp b/ipc/mscom/Interceptor.cpp
index bf216fabba31..88d1d7efadaf 100644
--- a/ipc/mscom/Interceptor.cpp
+++ b/ipc/mscom/Interceptor.cpp
@@ -305,7 +305,6 @@ Interceptor::MapEntry*
 Interceptor::Lookup(REFIID aIid)
 {
   mMutex.AssertCurrentThreadOwns();
-
   for (uint32_t index = 0, len = mInterceptorMap.Length(); index < len; ++index) {
     if (mInterceptorMap[index].mIID == aIid) {
       return &mInterceptorMap[index];
@@ -368,57 +367,15 @@ Interceptor::CreateInterceptor(REFIID aIid, IUnknown* aOuter, IUnknown** aOutput
 }
 
 HRESULT
-Interceptor::PublishTarget(detail::LiveSetAutoLock& aLiveSetLock,
-                           RefPtr<IUnknown> aInterceptor,
-                           REFIID aTargetIid,
-                           STAUniquePtr<IUnknown> aTarget)
-{
-  RefPtr<IWeakReference> weakRef;
-  HRESULT hr = GetWeakReference(getter_AddRefs(weakRef));
-  if (FAILED(hr)) {
-    return hr;
-  }
-
-  // mTarget is a weak reference to aTarget. This is safe because we transfer
-  // ownership of aTarget into mInterceptorMap which remains live for the
-  // lifetime of this Interceptor.
-  mTarget = ToInterceptorTargetPtr(aTarget);
-  GetLiveSet().Put(mTarget.get(), weakRef.forget());
-
-  // Now we transfer aTarget's ownership into mInterceptorMap.
-  mInterceptorMap.AppendElement(MapEntry(aTargetIid,
-                                         aInterceptor,
-                                         aTarget.release()));
-
-  // Release the live set lock because subsequent operations may post work to
-  // the main thread, creating potential for deadlocks.
-  aLiveSetLock.Unlock();
-  return S_OK;
-}
-
-HRESULT
-Interceptor::GetInitialInterceptorForIID(detail::LiveSetAutoLock& aLiveSetLock,
+Interceptor::GetInitialInterceptorForIID(detail::LiveSetAutoLock& aLock,
                                          REFIID aTargetIid,
                                          STAUniquePtr<IUnknown> aTarget,
                                          void** aOutInterceptor)
 {
   MOZ_ASSERT(aOutInterceptor);
-  MOZ_ASSERT(aTargetIid != IID_IMarshal);
+  MOZ_ASSERT(aTargetIid != IID_IUnknown && aTargetIid != IID_IMarshal);
   MOZ_ASSERT(!IsProxy(aTarget.get()));
 
-  if (aTargetIid == IID_IUnknown) {
-    // We must lock ourselves so that nothing can race with us once we have been
-    // published to the live set.
-    AutoLock lock(*this);
-
-    HRESULT hr = PublishTarget(aLiveSetLock, nullptr, aTargetIid, Move(aTarget));
-    if (FAILED(hr)) {
-      return hr;
-    }
-
-    return QueryInterface(aTargetIid, aOutInterceptor);
-  }
-
   // Raise the refcount for stabilization purposes during aggregation
   RefPtr<IUnknown> kungFuDeathGrip(static_cast<IUnknown*>(
         static_cast<WeakReferenceSupport*>(this)));
@@ -442,15 +399,27 @@ Interceptor::GetInitialInterceptorForIID(detail::LiveSetAutoLock& aLiveSetLock,
     return hr;
   }
 
-  // We must lock ourselves so that nothing can race with us once we have been
-  // published to the live set.
-  AutoLock lock(*this);
-
-  hr = PublishTarget(aLiveSetLock, unkInterceptor, aTargetIid, Move(aTarget));
+  RefPtr<IWeakReference> weakRef;
+  hr = GetWeakReference(getter_AddRefs(weakRef));
   if (FAILED(hr)) {
     return hr;
   }
 
+  // mTarget is a weak reference to aTarget. This is safe because we transfer
+  // ownership of aTarget into mInterceptorMap which remains live for the
+  // lifetime of this Interceptor.
+  mTarget = ToInterceptorTargetPtr(aTarget);
+  GetLiveSet().Put(mTarget.get(), weakRef.forget());
+
+  // Release the live set lock because GetInterceptorForIID will post work to
+  // the main thread, creating potential for deadlocks.
+  aLock.Unlock();
+
+  // Now we transfer aTarget's ownership into mInterceptorMap.
+  mInterceptorMap.AppendElement(MapEntry(aTargetIid,
+                                         unkInterceptor,
+                                         aTarget.release()));
+
   if (mEventSink->MarshalAs(aTargetIid) == aTargetIid) {
     return unkInterceptor->QueryInterface(aTargetIid, aOutInterceptor);
   }
diff --git a/ipc/mscom/Interceptor.h b/ipc/mscom/Interceptor.h
index 7214a0e6592d..7e09528f73d1 100644
--- a/ipc/mscom/Interceptor.h
+++ b/ipc/mscom/Interceptor.h
@@ -120,7 +120,7 @@ private:
 private:
   explicit Interceptor(IInterceptorSink* aSink);
   ~Interceptor();
-  HRESULT GetInitialInterceptorForIID(detail::LiveSetAutoLock& aLiveSetLock,
+  HRESULT GetInitialInterceptorForIID(detail::LiveSetAutoLock& aLock,
                                       REFIID aTargetIid,
                                       STAUniquePtr<IUnknown> aTarget,
                                       void** aOutInterface);
@@ -129,10 +129,6 @@ private:
   HRESULT ThreadSafeQueryInterface(REFIID aIid,
                                    IUnknown** aOutInterface) override;
   HRESULT CreateInterceptor(REFIID aIid, IUnknown* aOuter, IUnknown** aOutput);
-  HRESULT PublishTarget(detail::LiveSetAutoLock& aLiveSetLock,
-                        RefPtr<IUnknown> aInterceptor,
-                        REFIID aTargetIid,
-                        STAUniquePtr<IUnknown> aTarget);
 
 private:
   InterceptorTargetPtr<IUnknown>  mTarget;
diff --git a/ipc/mscom/WeakRef.cpp b/ipc/mscom/WeakRef.cpp
index ffdb89be4dfa..cf71d2faf1d2 100644
--- a/ipc/mscom/WeakRef.cpp
+++ b/ipc/mscom/WeakRef.cpp
@@ -109,18 +109,6 @@ WeakReferenceSupport::~WeakReferenceSupport()
   ::DeleteCriticalSection(&mCSForQI);
 }
 
-void
-WeakReferenceSupport::Lock()
-{
-  ::EnterCriticalSection(&mCSForQI);
-}
-
-void
-WeakReferenceSupport::Unlock()
-{
-  ::LeaveCriticalSection(&mCSForQI);
-}
-
 HRESULT
 WeakReferenceSupport::QueryInterface(REFIID riid, void** ppv)
 {
diff --git a/ipc/mscom/WeakRef.h b/ipc/mscom/WeakRef.h
index fcc623e430f1..99c0886b9e82 100644
--- a/ipc/mscom/WeakRef.h
+++ b/ipc/mscom/WeakRef.h
@@ -12,7 +12,6 @@
 
 #include "mozilla/Assertions.h"
 #include "mozilla/Atomics.h"
-#include "mozilla/Mutex.h"
 #include "mozilla/RefPtr.h"
 #include "nsISupportsImpl.h"
 
@@ -102,12 +101,6 @@ protected:
   virtual HRESULT ThreadSafeQueryInterface(REFIID aIid,
                                            IUnknown** aOutInterface) = 0;
 
-  void Lock();
-  void Unlock();
-
-  typedef BaseAutoLock<WeakReferenceSupport> AutoLock;
-  friend class AutoLock;
-
 private:
   RefPtr<detail::SharedRef> mSharedRef;
   ULONG                     mRefCnt;