Add linux_memcheck as default trybot.

Add linux_memcheck as default trybot.

After moving to Swarming, this bot executes in ~20 minutes
instead of hours, making it a good candidate for pre-submit
checks. It would have caught the leak that led to the revert
in https://codereview.webrtc.org/2649113003/ if it would have run.

BUG=chromium:497757
TBR=ehmaldonado@webrtc.org

Review-Url: https://codereview.webrtc.org/2649353002 .
Cr-Commit-Position: refs/heads/master@{#16226}
Committed: https://chromium.googlesource.com/external/webrtc/+/2b7552663e8f8923118c92ae07c3563a3b8e1aa6

[kjellander_webrtc, 2017-01-24 04:22:45]

Description was changed from

==========
Add linux_memcheck as default trybot.

After moving to Swarming, this bot executes in ~20 minutes
instead of hours, making it a good candidate for pre-submit
checks. It would have caught the leak that led to the revert
in https://codereview.webrtc.org/2649113003/ if it would have run.

BUG=chromium:497757
TBR=ehmaldonado@webrtc.org
==========

to

==========
Add linux_memcheck as default trybot.

After moving to Swarming, this bot executes in ~20 minutes
instead of hours, making it a good candidate for pre-submit
checks. It would have caught the leak that led to the revert
in https://codereview.webrtc.org/2649113003/ if it would have run.

BUG=chromium:497757
TBR=ehmaldonado@webrtc.org

Review-Url: https://codereview.webrtc.org/2649353002 .
Cr-Commit-Position: refs/heads/master@{#16226}
Committed:
https://chromium.googlesource.com/external/webrtc/+/2b7552663e8f8923118c92ae0...
==========

[kjellander_webrtc, 2017-01-24 04:22:46]

Committed patchset #1 (id:1) manually as
2b7552663e8f8923118c92ae07c3563a3b8e1aa6 (presubmit successful).

[ehmaldonado_webrtc, 2017-01-24 06:37:56]

On 2017/01/24 04:22:46, kjellander_webrtc wrote:
> Committed patchset #1 (id:1) manually as
> 2b7552663e8f8923118c92ae07c3563a3b8e1aa6 (presubmit successful).

lgtm