Add comment explaining fix and added explicit HistoryService dependency in predictor.

Add comment explaining fix and added explicit HistoryService dependency in predictor.

R=scottbyer@chromium.org,shishir@chromium.org
BUG=140466
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=150120

[Shishir, 2012-08-03 21:03:02]

lgtm

[Scott Byer, 2012-08-03 21:04:44]

lgtm

[commit-bot: I haz the power, 2012-08-03 21:12:15]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dominich@chromium.org/10825188/1

[commit-bot: I haz the power, 2012-08-03 21:37:23]

Try job failure for 10825188-1 (retry) on win_rel for step "compile" (clobber
build).
It's a second try, previously, step "compile" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[commit-bot: I haz the power, 2012-08-03 21:39:06]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dominich@chromium.org/10825188/1

[commit-bot: I haz the power, 2012-08-03 21:57:17]

Try job failure for 10825188-1 (retry) on win_rel for step "compile" (clobber
build).
It's a second try, previously, step "compile" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[commit-bot: I haz the power, 2012-08-03 22:02:05]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dominich@chromium.org/10825188/1

[commit-bot: I haz the power, 2012-08-03 22:23:10]

Try job failure for 10825188-1 (retry) on win_rel for step "compile" (clobber
build).
It's a second try, previously, step "compile" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[commit-bot: I haz the power, 2012-08-06 16:05:51]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dominich@chromium.org/10825188/1

[commit-bot: I haz the power, 2012-08-06 18:45:06]

Change committed as 150120