Adding stub files for RtpSender/RtpReceiver.

Adding stub files for RtpSender/RtpReceiver.

This will allow Chromium's build files to be updated, so that when the
real RtpSender CL is submitted, it doesn't break the FYI bots.

Committed: https://crrev.com/6979b024d7cebfdcd1e8f66da59ea157bbc9e47e
Cr-Commit-Position: refs/heads/master@{#10065}

[Taylor Brandstetter, 2015-09-23 17:57:23]

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

[pthatcher1, 2015-09-23 18:12:32]

lgtm

[Taylor Brandstetter, 2015-09-23 18:19:57]

The CQ bit was checked by deadbeef@webrtc.org

[commit-bot: I haz the power, 2015-09-23 18:20:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1364813004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1364813004/1

[commit-bot: I haz the power, 2015-09-23 18:22:19]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-23 18:22:20]

Try jobs failed on following builders:
  presubmit on tryserver.webrtc (JOB_FAILED,
http://build.chromium.org/p/tryserver.webrtc/builders/presubmit/builds/906)

[Taylor Brandstetter, 2015-09-24 23:46:31]

The CQ bit was checked by deadbeef@webrtc.org

[Taylor Brandstetter, 2015-09-24 23:46:31]

The patchset sent to the CQ was uploaded after l-g-t-m from pthatcher@webrtc.org
Link to the patchset: https://codereview.webrtc.org/1364813004/#ps20001 (title:
"Expanding stubs so they pass presubmit checks...")

[commit-bot: I haz the power, 2015-09-24 23:46:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1364813004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1364813004/20001

[commit-bot: I haz the power, 2015-09-24 23:47:58]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-24 23:48:08]

Patchset 2 (id:??) landed as
https://crrev.com/6979b024d7cebfdcd1e8f66da59ea157bbc9e47e
Cr-Commit-Position: refs/heads/master@{#10065}