Add new step graph type to event log visualization tool

Add new step graph type to event log visualization tool. Currently used for bitrate estimate and accumulated packet count, but could in general be used for any metric that is piecewise constant.

BUG=None

Review-Url: https://codereview.webrtc.org/2653343004
Cr-Commit-Position: refs/heads/master@{#16399}
Committed: https://chromium.googlesource.com/external/webrtc/+/77f0580f83c4ee0b85f71e64b227711c26b2ecab

[terelius, 2017-01-26 11:44:51]

The CQ bit was checked by terelius@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2017-01-26 11:45:00]

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

[terelius, 2017-01-26 11:45:59]

terelius@webrtc.org changed reviewers:
+ philipel@webrtc.org, stefan@webrtc.org

[commit-bot: I haz the power, 2017-01-26 12:47:04]

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

[commit-bot: I haz the power, 2017-01-26 12:47:04]

Dry run: This issue passed the CQ dry run.

[philipel, 2017-01-30 09:38:42]

lgtm

[terelius, 2017-02-01 13:40:01]

stefan, do you have any comments?

[stefan-webrtc, 2017-02-01 13:51:48]

lgtm

[terelius, 2017-02-01 13:52:20]

The CQ bit was checked by terelius@webrtc.org

[commit-bot: I haz the power, 2017-02-01 13:52:25]

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, 2017-02-01 14:34:54]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1485957140418550, "parent_rev":
"a565f92e879f747ca4028d205f77e35ec6d00150", "commit_rev":
"77f0580f83c4ee0b85f71e64b227711c26b2ecab"}

[commit-bot: I haz the power, 2017-02-01 14:34:56]

Description was changed from

==========
Add new step graph type to event log visualization tool. Currently used for
bitrate estimate and accumulated packet count, but could in general be used for
any metric that is piecewise constant.

BUG=None
==========

to

==========
Add new step graph type to event log visualization tool. Currently used for
bitrate estimate and accumulated packet count, but could in general be used for
any metric that is piecewise constant.

BUG=None

Review-Url: https://codereview.webrtc.org/2653343004
Cr-Commit-Position: refs/heads/master@{#16399}
Committed:
https://chromium.googlesource.com/external/webrtc/+/77f0580f83c4ee0b85f71e64b...
==========

[commit-bot: I haz the power, 2017-02-01 14:34:57]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/77f0580f83c4ee0b85f71e64b...