Revert of [Telemetry] Refactor Chrome devtools tracing

Revert of [Telemetry] Refactor Chrome devtools tracing (patchset #2 id:20001 of https://codereview.chromium.org/1338033002/ )

Reason for revert:
This CL fails on mojo perf bots. For Chrome, Telemetry waits for Chrome for the devtools port number. But for mojo, telemetry gives the port number to mandoline. Revert for now, will work on a fix.

See https://code.google.com/p/chromium/issues/detail?id=531755

Original issue's description:
> [Telemetry] Refactor Chrome devtools tracing
>
> Platform-level tracing doc:
> https://docs.google.com/document/d/1Uv8SzOq2ugvzLiOcP85g7qPiaxwsn4tgOdxpe3YjUkM/edit?usp=sharing
>
> BUG=515323
>
> Committed: https://crrev.com/cbecca3af4042fbf593dead4c12cfdd22cfd2310
> Cr-Commit-Position: refs/heads/master@{#348740}

TBR=nednguyen@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=515323
Committed: https://crrev.com/df1e976e0ac698a96f062138404ea628c56efe1f
Cr-Commit-Position: refs/heads/master@{#348782}

[Zhen Wang, 2015-09-15 00:02:57]

Created Revert of [Telemetry] Refactor Chrome devtools tracing

[commit-bot: I haz the power, 2015-09-15 00:04:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1343883002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1343883002/1

[commit-bot: I haz the power, 2015-09-15 00:07:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-15 00:07:51]

Patchset 1 (id:??) landed as
https://crrev.com/df1e976e0ac698a96f062138404ea628c56efe1f
Cr-Commit-Position: refs/heads/master@{#348782}

[commit-bot: I haz the power, 2015-09-23 12:39:52]

Patchset 1 (id:??) landed as
https://crrev.com/df1e976e0ac698a96f062138404ea628c56efe1f
Cr-Commit-Position: refs/heads/master@{#348782}