diff -r 000000000000 -r 6474c204b198 content/media/fmp4/PlatformDecoderModule.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/media/fmp4/PlatformDecoderModule.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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 "PlatformDecoderModule.h"
+#ifdef XP_WIN
+#include "WMFDecoderModule.h"
+#endif
+#ifdef MOZ_FFMPEG
+#include "FFmpegDecoderModule.h"
+#endif
+#include "mozilla/Preferences.h"
+
+namespace mozilla {
+
+extern PlatformDecoderModule* CreateBlankDecoderModule();
+
+bool PlatformDecoderModule::sUseBlankDecoder = false;
+bool PlatformDecoderModule::sFFmpegDecoderEnabled = false;
+
+/* static */
+void
+PlatformDecoderModule::Init()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  static bool alreadyInitialized = false;
+  if (alreadyInitialized) {
+    return;
+  }
+  alreadyInitialized = true;
+
+  Preferences::AddBoolVarCache(&sUseBlankDecoder,
+                               "media.fragmented-mp4.use-blank-decoder");
+  Preferences::AddBoolVarCache(&sFFmpegDecoderEnabled,
+                               "media.fragmented-mp4.ffmpeg.enabled", false);
+
+#ifdef XP_WIN
+  WMFDecoderModule::Init();
+#endif
+}
+
+/* static */
+PlatformDecoderModule*
+PlatformDecoderModule::Create()
+{
+  if (sUseBlankDecoder) {
+    return CreateBlankDecoderModule();
+  }
+#ifdef XP_WIN
+  nsAutoPtr<WMFDecoderModule> m(new WMFDecoderModule());
+  if (NS_SUCCEEDED(m->Startup())) {
+    return m.forget();
+  }
+#endif
+#ifdef MOZ_FFMPEG
+  if (sFFmpegDecoderEnabled) {
+    return new FFmpegDecoderModule();
+  }
+#endif
+  return nullptr;
+}
+
+} // namespace mozilla