Revert of Remove AudioTrackRenderer

talk/app/webrtc/audiotrackrenderer.cc

Index: talk/app/webrtc/audiotrackrenderer.cc
diff --git a/talk/app/webrtc/audiotrackrenderer.cc b/talk/app/webrtc/audiotrackrenderer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..264a3cb73485201c933e4082c036c9a0dce6c4f4
--- /dev/null
+++ b/talk/app/webrtc/audiotrackrenderer.cc
@@ -0,0 +1,49 @@
+/*
+ * libjingle
+ * Copyright 2013 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "talk/app/webrtc/audiotrackrenderer.h"
+#include "webrtc/base/common.h"
+
+namespace webrtc {
+
+AudioTrackRenderer::AudioTrackRenderer() : channel_id_(-1) {
+}
+
+AudioTrackRenderer::~AudioTrackRenderer() {
+}
+
+void AudioTrackRenderer::AddChannel(int channel_id) {
+  ASSERT(channel_id_ == -1 || channel_id_ == channel_id);
+  channel_id_ = channel_id;
+}
+
+void AudioTrackRenderer::RemoveChannel(int channel_id) {
+  ASSERT(channel_id_ == -1 || channel_id_ == channel_id);
+  channel_id_ = -1;
+}
+
+}  // namespace webrtc