The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/af9b3851304ba19e7134478ae0520ad0d7600b99

commit af9b3851304ba19e7134478ae0520ad0d7600b99
Author: Guido Urdaneta <guidou@chromium.org>
Date: Wed May 30 15:43:00 2018

Make AudioTracks()/VideoTracks() accessors of WebMediaStream return values.

Currently, these accessors take an output argument, which makes code more
difficult to read and write.
The rationale of the old accessors was to avoid an extra copy, but this is
no longer an issue since WebVector now has a move constructor and a move
assignment operator both of which just swap the underlying std::vector.

No functionality change intended.

Bug:  846363 
Change-Id: I09a1901a48d874342383e8a3366e398c0d115a73
Reviewed-on: https://chromium-review.googlesource.com/1071533
Commit-Queue: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Henrik Boström <hbos@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#562843}
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/pepper/pepper_to_video_track_adapter_unittest.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/pepper/video_track_to_pepper_adapter.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/stream/media_stream_renderer_factory_impl.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/stream/user_media_client_impl_unittest.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/stream/user_media_processor.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/stream/webmediaplayer_ms.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/stream/webmediaplayer_ms_compositor.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/webrtc/media_stream_video_webrtc_sink_unittest.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/webrtc/peer_connection_tracker.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/webrtc/rtc_peer_connection_handler_unittest.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/webrtc/webrtc_audio_renderer.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/webrtc/webrtc_media_stream_adapter.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media/webrtc/webrtc_media_stream_adapter_unittest.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/renderer/media_recorder/media_recorder_handler.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/content/shell/renderer/layout_test/test_media_stream_renderer_factory.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/third_party/blink/public/platform/web_media_stream.h
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/third_party/blink/renderer/modules/mediacapturefromelement/html_media_element_capture.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/third_party/blink/renderer/modules/peerconnection/rtc_peer_connection.cc
[modify] https://crrev.com/af9b3851304ba19e7134478ae0520ad0d7600b99/third_party/blink/renderer/platform/exported/web_media_stream.cc

[bulk-edit: disregard if N/A] Can the owner please set milestone to this bug if applicable?