talk: DataChannel.java repeated contents. This removes the duplicate.
talk: DataChannel.java repeated contents. This removes the duplicate.

TBR=ajm

BUG=N/A

Review URL: https://webrtc-codereview.appspot.com/1825004

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 8c7347124c2760cbf1340759253e7f046490d10e

sippet/talk,sippet/talk,sippet/talk,sippet/talk,sippet/talk