Revert of Omnibox: Make URLs of Bookmarks Searchable

Revert of Omnibox: Make URLs of Bookmarks Searchable (patchset #2 of https://codereview.chromium.org/489373005/)

Reason for revert:
Broke interactive_ui_tests on mac: https://build.chromium.org/p/chromium.mac/builders/Mac%2010.6%20Tests%20(dbg)(1)/builds/52199

Original issue's description:
> Omnibox: Make URLs of Bookmarks Searchable
> 
> This used to be controlled by a field trial created in
> https://codereview.chromium.org/184663002
> 
> After evaluating this change, we've decided to launch it.
> This change turns the flag on by default and removes the field trial code.
> It also removes the index_urls_ parameters everywhere because those will
> always be true forevermore.
> 
> I tested this interactively.
> Also, all the unit tests still apparently pass.  And yes some of these do
> exercise this feature.
> 
> TBR=joaodasilva
> (for trivial change to components/policy/core/browser/managed_bookmarks_tracker_unittest.cc )
> 
> BUG=157204, 378854
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=291445

TBR=pkasting@google.com,sky@chromium.org,pkasting@chromium.org,mpearson@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=157204, 378854
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=291496

[Evan Stade, 2014-08-22 20:35:11]

Created Revert of Omnibox: Make URLs of Bookmarks Searchable

[commit-bot: I haz the power, 2014-08-22 20:35:25]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/estade@chromium.org/485483003/1

[commit-bot: I haz the power, 2014-08-22 20:37:21]

Committed patchset #1 (1) as 291496