tree cb29af0c9d9a8e21a399c93d914acfdbb3c64e7b
parent d5c93e0be18f8bf2ed2f6dc69de3eca3a3e37f26
author zhihuang <zhihuang@webrtc.org> 1480722070 -0800
committer Commit bot <commit-bot@chromium.org> 1480722075 +0000

Modify the parameter type of PeerConnectionObserver callback OnAddTrack.

Change the second parameter type to a const reference of vector so that
the vector will not be copied.

BUG=none

Review-Url: https://codereview.webrtc.org/2551603003
Cr-Commit-Position: refs/heads/master@{#15396}