Timeline: bring back FirstPaint marker and remove brown ticks near frame markers

Timeline: bring back FirstPaint marker and remove brown ticks near frame markers

- implement synthetic FirstPaint markers on front-end (they used to be generated
    on the back-end with old Timeline instrumentation which is an ex-parrot)
- remove brown marks near the frame markers (regressed at r177959)

BUG=

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=185392

[caseq, 2014-11-14 18:10:58]

caseq@chromium.org changed reviewers:
+ pfeldman@chromium.org, yurys@chromium.org

[pfeldman, 2014-11-14 19:43:16]

lgtm.

[caseq, 2014-11-14 19:55:20]

The CQ bit was checked by caseq@chromium.org

[commit-bot: I haz the power, 2014-11-14 19:56:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/732683002/1

[commit-bot: I haz the power, 2014-11-14 21:20:40]

Committed patchset #1 (id:1) as 185392

[caseq, 2014-11-26 16:50:49]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/761493004/ by caseq@chromium.org.

The reason for reverting is: This is wrong as it processes trace events from
different trace threads and relied on their relative order. Let's do it right
from scratch so that it's easier to merge..