--- a/toolkit/xre/nsEmbedFunctions.cpp
+++ b/toolkit/xre/nsEmbedFunctions.cpp
@@ -52,16 +52,18 @@
 #include "base/message_loop.h"
 #include "base/process_util.h"
 #include "chrome/common/child_process.h"
 #if defined(MOZ_WIDGET_ANDROID)
 #include "chrome/common/ipc_channel.h"
 #include "mozilla/jni/Utils.h"
 #endif //  defined(MOZ_WIDGET_ANDROID)
 
+#include "mozilla/AbstractThread.h"
+
 #include "mozilla/ipc/BrowserProcessSubThread.h"
 #include "mozilla/ipc/GeckoChildProcessHost.h"
 #include "mozilla/ipc/IOThreadChild.h"
 #include "mozilla/ipc/ProcessChild.h"
 #include "ScopedXREEmbed.h"
 
 #include "mozilla/plugins/PluginProcessChild.h"
 #include "mozilla/dom/ContentProcess.h"
@@ -414,16 +416,20 @@ XRE_InitChildProcess(int aArgc,
   mozilla::LogModule::Init();
 
   char aLocal;
   GeckoProfilerInitRAII profiler(&aLocal);
 
   PROFILER_LABEL("Startup", "XRE_InitChildProcess",
     js::ProfileEntry::Category::OTHER);
 
+  // Ensure AbstractThread is minimally setup, so async IPC messages
+  // work properly.
+  AbstractThread::InitTLS();
+
   // Complete 'task_t' exchange for Mac OS X. This structure has the same size
   // regardless of architecture so we don't have any cross-arch issues here.
 #ifdef XP_MACOSX
   if (aArgc < 1)
     return NS_ERROR_FAILURE;
   const char* const mach_port_name = aArgv[--aArgc];
 
   const int kTimeoutMs = 1000;

--- a/xpcom/build/XPCOMInit.cpp
+++ b/xpcom/build/XPCOMInit.cpp
@@ -1,17 +1,16 @@
 /* -*- 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 "base/basictypes.h"
 
-#include "mozilla/AbstractThread.h"
 #include "mozilla/Atomics.h"
 #include "mozilla/Poison.h"
 #include "mozilla/SharedThreadPool.h"
 #include "mozilla/XPCOM.h"
 #include "nsXULAppAPI.h"
 
 #include "nsXPCOMPrivate.h"
 #include "nsXPCOMCIDInternal.h"
@@ -676,19 +675,16 @@ NS_InitXPCOM2(nsIServiceManager** aResul
 
   // Initialize the JS engine.
   const char* jsInitFailureReason = JS_InitWithFailureDiagnostic();
   if (jsInitFailureReason) {
     NS_RUNTIMEABORT(jsInitFailureReason);
   }
   sInitializedJS = true;
   
-  // Init AbstractThread.
-  AbstractThread::InitStatics();
-
   rv = nsComponentManagerImpl::gComponentManager->Init();
   if (NS_FAILED(rv)) {
     NS_RELEASE(nsComponentManagerImpl::gComponentManager);
     return rv;
   }
 
   if (aResult) {
     NS_ADDREF(*aResult = nsComponentManagerImpl::gComponentManager);
@@ -786,17 +782,16 @@ NS_InitMinimalXPCOM()
     return rv;
   }
 
   // Global cycle collector initialization.
   if (!nsCycleCollector_init()) {
     return NS_ERROR_UNEXPECTED;
   }
 
-  AbstractThread::InitStatics();
   SharedThreadPool::InitStatics();
   mozilla::Telemetry::Init();
   mozilla::HangMonitor::Startup();
   mozilla::BackgroundHangMonitor::Startup();
 
   return NS_OK;
 }
 

--- a/xpcom/threads/AbstractThread.cpp
+++ b/xpcom/threads/AbstractThread.cpp
@@ -246,17 +246,25 @@ AbstractThread::RequiresTailDispatchFrom
 AbstractThread*
 AbstractThread::MainThread()
 {
   MOZ_ASSERT(sMainThread);
   return sMainThread;
 }
 
 void
-AbstractThread::InitStatics()
+AbstractThread::InitTLS()
+{
+  if (!sCurrentThreadTLS.init()) {
+    MOZ_CRASH();
+  }
+}
+
+void
+AbstractThread::InitMainThread()
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(!sMainThread);
   nsCOMPtr<nsIThread> mainThread;
   NS_GetMainThread(getter_AddRefs(mainThread));
   MOZ_DIAGNOSTIC_ASSERT(mainThread);
   sMainThread = new EventTargetWrapper(mainThread.get(), /* aRequireTailDispatch = */ true);
   ClearOnShutdown(&sMainThread);

--- a/xpcom/threads/AbstractThread.h
+++ b/xpcom/threads/AbstractThread.h
@@ -90,17 +90,18 @@ public:
   virtual nsIEventTarget* AsEventTarget() { MOZ_CRASH("Not an event target!"); }
 
   // Returns the non-DocGroup version of AbstractThread on the main thread.
   // A DocGroup-versioned one is available in DispatcherTrait::AbstractThreadFor().
   // Note: DispatcherTrait::AbstractThreadFor() SHALL be used when possible.
   static AbstractThread* MainThread();
 
   // Must be called exactly once during startup.
-  static void InitStatics();
+  static void InitTLS();
+  static void InitMainThread();
 
   void DispatchStateChange(already_AddRefed<nsIRunnable> aRunnable);
 
   static void DispatchDirectTask(already_AddRefed<nsIRunnable> aRunnable);
 
   // Create a runnable that will run |aRunnable| and drain the direct tasks
   // generated by it.
   virtual already_AddRefed<nsIRunnable>

--- a/xpcom/threads/nsThreadManager.cpp
+++ b/xpcom/threads/nsThreadManager.cpp
@@ -5,16 +5,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsThreadManager.h"
 #include "nsThread.h"
 #include "nsThreadUtils.h"
 #include "nsIClassInfoImpl.h"
 #include "nsTArray.h"
 #include "nsAutoPtr.h"
+#include "mozilla/AbstractThread.h"
 #include "mozilla/ThreadLocal.h"
 #ifdef MOZ_CANARY
 #include <fcntl.h>
 #include <unistd.h>
 #endif
 
 #include "MainThreadIdlePeriod.h"
 
@@ -105,16 +106,20 @@ nsThreadManager::Init()
     nsCOMPtr<nsIIdlePeriod> idlePeriod = new MainThreadIdlePeriod();
     mMainThread->RegisterIdlePeriod(idlePeriod.forget());
   }
 
   // We need to keep a pointer to the current thread, so we can satisfy
   // GetIsMainThread calls that occur post-Shutdown.
   mMainThread->GetPRThread(&mMainPRThread);
 
+  // Init AbstractThread.
+  AbstractThread::InitTLS();
+  AbstractThread::InitMainThread();
+
   mInitialized = true;
   return NS_OK;
 }
 
 void
 nsThreadManager::Shutdown()
 {
   MOZ_ASSERT(NS_IsMainThread(), "shutdown not called from main thread");