[webkitpy] Merge ChromiumBuildBot class into the BuildBot class.

[webkitpy] Merge ChromiumBuildBot class into the BuildBot class.

Move the ChromiumBuildBot class logic into the BuildBot class.
Also remove some workarounds for detecting if the builder is a
Chromium builder.

BUG=none

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=183408

[elecro, 2014-10-07 12:30:16]

pgal.u-szeged@partner.samsung.com changed reviewers:
+ abarth@chromium.org, dpranke@chromium.org

[elecro, 2014-10-07 18:08:29]

PTAL

[Dirk Pranke, 2014-10-08 01:40:39]

lgtm

[elecro, 2014-10-08 08:15:30]

The CQ bit was checked by pgal.u-szeged@partner.samsung.com

[commit-bot: I haz the power, 2014-10-08 08:15:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/638573002/1

[commit-bot: I haz the power, 2014-10-08 10:29:47]

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

[commit-bot: I haz the power, 2014-10-08 10:29:48]

Try jobs failed on following builders:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/2...)

[elecro, 2014-10-08 10:38:47]

The CQ bit was checked by pgal.u-szeged@partner.samsung.com

[commit-bot: I haz the power, 2014-10-08 10:39:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/638573002/1

[commit-bot: I haz the power, 2014-10-08 11:42:48]

Committed patchset #1 (id:1) as 183408