Delete unused classes DesktopId and ScreencastEventCatcher.

Delete unused classes DesktopId and ScreencastEventCatcher.

BUG=webrtc:6424
Review-Url: https://codereview.webrtc.org/2650703002
Cr-Commit-Position: refs/heads/master@{#16228}
Committed: https://chromium.googlesource.com/external/webrtc/+/c23b0b26df0ed7d482729dbdc47137ed7a7db788

[nisse-webrtc, 2017-01-23 12:19:20]

nisse@webrtc.org changed reviewers:
+ pthatcher@webrtc.org

[nisse-webrtc, 2017-01-23 12:19:21]

These classes appear unused. I found them on the list produced by
webrtc/tools/class_usage.sh.

[pthatcher1, 2017-01-23 21:32:17]

lgtm

[nisse-webrtc, 2017-01-24 07:26:40]

The CQ bit was checked by nisse@webrtc.org

[commit-bot: I haz the power, 2017-01-24 07:26:45]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-01-24 08:03:32]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1485242800326630, "parent_rev":
"ad452287b04060b01c9137ec6b22524401ce4e98", "commit_rev":
"c23b0b26df0ed7d482729dbdc47137ed7a7db788"}

[commit-bot: I haz the power, 2017-01-24 08:03:35]

Description was changed from

==========
Delete unused classes DesktopId and ScreencastEventCatcher.

BUG=webrtc:6424
==========

to

==========
Delete unused classes DesktopId and ScreencastEventCatcher.

BUG=webrtc:6424

Review-Url: https://codereview.webrtc.org/2650703002
Cr-Commit-Position: refs/heads/master@{#16228}
Committed:
https://chromium.googlesource.com/external/webrtc/+/c23b0b26df0ed7d482729dbdc...
==========

[commit-bot: I haz the power, 2017-01-24 08:03:36]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/c23b0b26df0ed7d482729dbdc...