--- a/content/media/webspeech/synth/pico/nsPicoService.cpp
+++ b/content/media/webspeech/synth/pico/nsPicoService.cpp
@@ -406,52 +406,51 @@ NS_IMETHODIMP
 PicoCallbackRunnable::OnCancel()
 {
   mService->mCurrentTask = nullptr;
   return NS_OK;
 }
 
 NS_INTERFACE_MAP_BEGIN(nsPicoService)
   NS_INTERFACE_MAP_ENTRY(nsISpeechService)
-  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsISpeechService)
+  NS_INTERFACE_MAP_ENTRY(nsIObserver)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIObserver)
 NS_INTERFACE_MAP_END
 
 NS_IMPL_ADDREF(nsPicoService)
 NS_IMPL_RELEASE(nsPicoService)
 
-nsPicoService::nsPicoService()
-  : mInitialized(false)
-  , mVoicesMonitor("nsPicoService::mVoices")
-  , mCurrentTask(nullptr)
-  , mPicoSystem(nullptr)
-  , mPicoEngine(nullptr)
-  , mSgResource(nullptr)
-  , mTaResource(nullptr)
-  , mPicoMemArea(nullptr)
-{
-  DebugOnly<nsresult> rv = NS_NewNamedThread("Pico Worker", getter_AddRefs(mThread));
-  MOZ_ASSERT(NS_SUCCEEDED(rv));
-  rv = mThread->Dispatch(NS_NewRunnableMethod(this, &nsPicoService::Init), NS_DISPATCH_NORMAL);
-  MOZ_ASSERT(NS_SUCCEEDED(rv));
-}
-
 nsPicoService::~nsPicoService()
 {
   // We don't worry about removing the voices because this gets
   // destructed at shutdown along with the voice registry.
   MonitorAutoLock autoLock(mVoicesMonitor);
   mVoices.Clear();
 
   if (mThread) {
     mThread->Shutdown();
   }
 
   UnloadEngine();
 }
 
+// nsIObserver
+
+NS_IMETHODIMP
+nsPicoService::Observe(nsISupports* aSubject, const char* aTopic,
+                       const char16_t* aData)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  NS_ENSURE_TRUE(!strcmp(aTopic, "profile-after-change"), NS_ERROR_UNEXPECTED);
+
+  DebugOnly<nsresult> rv = NS_NewNamedThread("Pico Worker", getter_AddRefs(mThread));
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  return mThread->Dispatch(
+    NS_NewRunnableMethod(this, &nsPicoService::Init), NS_DISPATCH_NORMAL);
+}
 // nsISpeechService
 
 NS_IMETHODIMP
 nsPicoService::Speak(const nsAString& aText, const nsAString& aUri,
                      float aRate, float aPitch, nsISpeechTask* aTask)
 {
   NS_ENSURE_TRUE(mInitialized, NS_ERROR_NOT_AVAILABLE);
 

--- a/content/media/webspeech/synth/pico/nsPicoService.h
+++ b/content/media/webspeech/synth/pico/nsPicoService.h
@@ -5,42 +5,43 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef nsPicoService_h
 #define nsPicoService_h
 
 #include "mozilla/Mutex.h"
 #include "nsAutoPtr.h"
 #include "nsTArray.h"
+#include "nsIObserver.h"
 #include "nsIThread.h"
 #include "nsISpeechService.h"
 #include "nsRefPtrHashtable.h"
 #include "mozilla/StaticPtr.h"
 #include "mozilla/Monitor.h"
 
 namespace mozilla {
 namespace dom {
 
 class PicoVoice;
 class PicoCallbackRunnable;
 
 typedef void* pico_System;
 typedef void* pico_Resource;
 typedef void* pico_Engine;
 
-class nsPicoService : public nsISpeechService
+class nsPicoService : public nsIObserver,
+                      public nsISpeechService
 {
   friend class PicoCallbackRunnable;
   friend class PicoInitRunnable;
 
 public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSISPEECHSERVICE
-
-  nsPicoService();
+  NS_DECL_NSIOBSERVER
 
   static nsPicoService* GetInstance();
 
   static already_AddRefed<nsPicoService> GetInstanceForService();
 
   static void Shutdown();
 
 private:
@@ -77,14 +78,25 @@ private:
 
   pico_Resource mSgResource;
 
   pico_Resource mTaResource;
 
   nsAutoPtr<uint8_t> mPicoMemArea;
 
   static StaticRefPtr<nsPicoService> sSingleton;
+
+protected:
+  nsPicoService() : mInitialized(false)
+                  , mVoicesMonitor("nsPicoService::mVoices")
+                  , mCurrentTask(nullptr)
+                  , mPicoSystem(nullptr)
+                  , mPicoEngine(nullptr)
+                  , mSgResource(nullptr)
+                  , mTaResource(nullptr)
+                  , mPicoMemArea(nullptr)
+  {
+  }
 };
-
 } // namespace dom
 } // namespace mozilla
 
 #endif