ThreadWacther - delete the code for Android that collected stats for

ThreadWacther - delete the code for Android that collected stats for
StartupTimeBombAlarm.

Added a TODO to enable StartupTimeBomb for Android.

Reverting the following two CL's manaually:

https://codereview.chromium.org/269763002
https://codereview.chromium.org/273963002

R=jar@chromium.org
BUG=366699
Committed: https://crrev.com/9d4b477394fa54b89cda588c432da19b193d26a6
Cr-Commit-Position: refs/heads/master@{#300972}

[jar (doing other things), 2014-10-23 19:55:32]

For histograms.xml, better is to <obsolete> the histograms.

[ramant (doing other things), 2014-10-23 20:21:23]

PTAL

[jar (doing other things), 2014-10-23 21:42:13]

lgtm

[ramant (doing other things), 2014-10-23 21:42:27]

The CQ bit was checked by rtenneti@chromium.org

[commit-bot: I haz the power, 2014-10-23 21:45:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/672973002/20001

[commit-bot: I haz the power, 2014-10-23 23:09:50]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-10-23 23:10:09]

Patchset 2 (id:??) landed as
https://crrev.com/9d4b477394fa54b89cda588c432da19b193d26a6
Cr-Commit-Position: refs/heads/master@{#300972}