Add MP3 decoder and integrate with MP3 demuxer

dom/media/MP3Decoder.cpp

@@ -0,0 +1,45 @@
+
+/* -*- 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 "MP3Decoder.h"
+#include "MediaDecoderStateMachine.h"
+#include "MediaFormatReader.h"
+#include "MP3Demuxer.h"
+#include "mozilla/Preferences.h"
+
+#ifdef MOZ_WIDGET_ANDROID
+#include "AndroidBridge.h"
+#endif
+
+namespace mozilla {
+
+MediaDecoder*
+MP3Decoder::Clone() {
+  if (!IsEnabled()) {
+    return nullptr;
+  }
+  return new MP3Decoder();
+}
+
+MediaDecoderStateMachine*
+MP3Decoder::CreateStateMachine() {
+  nsRefPtr<MediaDecoderReader> reader =
+      new MediaFormatReader(this, new mp3::MP3Demuxer(GetResource()));
+  return new MediaDecoderStateMachine(this, reader);
+}
+
+bool
+MP3Decoder::IsEnabled() {
+#ifdef MOZ_WIDGET_ANDROID
+  // We need android.media.MediaCodec which exists in API level 16 and higher.
+  return AndroidBridge::Bridge()->GetAPIVersion() >= 16;
+#else
+  return Preferences::GetBool("media.mp3.enabled");
+#endif
+}
+
+} // namespace mozilla