Generate and assign media track ids in demuxers.

content/renderer/media/webmediaplayer_ms_unittest.cc

 // Copyright 2015 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 <stddef.h>
 
 #include "content/public/renderer/media_stream_renderer_factory.h"
 #include "content/renderer/media/webmediaplayer_ms.h"
 #include "content/renderer/media/webmediaplayer_ms_compositor.h"
 #include "content/renderer/render_frame_impl.h"
@@ skipping 375 matching lines @@
   void repaint() override {}
   void durationChanged() override {}
   void sizeChanged() override;
   void playbackStateChanged() override {}
   void setWebLayer(blink::WebLayer* layer) override;
   blink::WebMediaPlayer::TrackId addAudioTrack(const blink::WebString& id,
                                                AudioTrackKind,
                                                const blink::WebString& label,
                                                const blink::WebString& language,
                                                bool enabled) override {
-    return 0;
+    return blink::WebMediaPlayer::TrackId();
   }
   void removeAudioTrack(blink::WebMediaPlayer::TrackId) override {}
   blink::WebMediaPlayer::TrackId addVideoTrack(const blink::WebString& id,
                                                VideoTrackKind,
                                                const blink::WebString& label,
                                                const blink::WebString& language,
                                                bool selected) override {
-    return 0;
+    return blink::WebMediaPlayer::TrackId();
   }
   void removeVideoTrack(blink::WebMediaPlayer::TrackId) override {}
   void addTextTrack(blink::WebInbandTextTrack*) override {}
   void removeTextTrack(blink::WebInbandTextTrack*) override {}
   void mediaSourceOpened(blink::WebMediaSource*) override {}
   void requestSeek(double) override {}
   void remoteRouteAvailabilityChanged(bool) override {}
   void connectedToRemoteDevice() override {}
   void disconnectedFromRemoteDevice() override {}
   void cancelledRemotePlaybackRequest() override {}
@@ skipping 409 matching lines @@
   EXPECT_TRUE(player_.paused());
 
   // OnShown() should restart after a forced suspension.
   player_.OnShown();
   EXPECT_FALSE(player_.paused());
   EXPECT_CALL(*this, DoSetWebLayer(false));
 }
 #endif
 
 }  // namespace content