diff -r 000000000000 -r 6474c204b198 dom/system/gonk/VolumeServiceIOThread.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/system/gonk/VolumeServiceIOThread.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,82 @@
+/* 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 "VolumeServiceIOThread.h"
+#include "base/message_loop.h"
+#include "nsVolumeService.h"
+#include "nsXULAppAPI.h"
+#include "Volume.h"
+#include "VolumeManager.h"
+
+namespace mozilla {
+namespace system {
+
+VolumeServiceIOThread::VolumeServiceIOThread(nsVolumeService* aVolumeService)
+  : mVolumeService(aVolumeService)
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+
+  VolumeManager::RegisterStateObserver(this);
+  Volume::RegisterObserver(this);
+  UpdateAllVolumes();
+}
+
+VolumeServiceIOThread::~VolumeServiceIOThread()
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+  Volume::UnregisterObserver(this);
+  VolumeManager::UnregisterStateObserver(this);
+}
+
+void
+VolumeServiceIOThread::Notify(Volume* const & aVolume)
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+  if (VolumeManager::State() != VolumeManager::VOLUMES_READY) {
+    return;
+  }
+  mVolumeService->UpdateVolumeIOThread(aVolume);
+}
+
+void
+VolumeServiceIOThread::Notify(const VolumeManager::StateChangedEvent& aEvent)
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+  UpdateAllVolumes();
+}
+
+void
+VolumeServiceIOThread::UpdateAllVolumes()
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+  if (VolumeManager::State() != VolumeManager::VOLUMES_READY) {
+    return;
+  }
+  VolumeManager::VolumeArray::size_type numVolumes = VolumeManager::NumVolumes();
+  VolumeManager::VolumeArray::index_type volIndex;
+
+  for (volIndex = 0; volIndex < numVolumes; volIndex++) {
+    RefPtr<Volume>  vol = VolumeManager::GetVolume(volIndex);
+    mVolumeService->UpdateVolumeIOThread(vol);
+  }
+}
+
+static StaticRefPtr<VolumeServiceIOThread> sVolumeServiceIOThread;
+
+void
+InitVolumeServiceIOThread(nsVolumeService* const & aVolumeService)
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+  sVolumeServiceIOThread = new VolumeServiceIOThread(aVolumeService);
+}
+
+void
+ShutdownVolumeServiceIOThread()
+{
+  MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
+  sVolumeServiceIOThread = nullptr;
+}
+
+} // system
+} // mozilla