Move Alsa device opening into the audio thread, and add in support for multi-channel audio.

media/base/media_switches.cc

Index: media/base/media_switches.cc
diff --git a/media/base/media_switches.cc b/media/base/media_switches.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f40ce26f1c73b81be7defaf3b7140b548a182f52
--- /dev/null
+++ b/media/base/media_switches.cc
@@ -0,0 +1,14 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/media_switches.h"
+
+namespace switches {
+
+#if defined(OS_LINUX)
+// The Alsa device to use when opening an audio stream.
+const char kAlsaDevice[] = "alsa-device";
+#endif
+
+}  // namespace switches