Fix incorrect number of matches and misleading highlighting in "Find on Page" results

Fix incorrect number of matches and misleading highlighting in "Find on Page" results.

BUG=397563
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179000

[Andrey Kraynov, 2014-07-25 17:16:55]

yosin@, could you please take a look at this CL and a bug that I've filed?
Could you explain what behavior is expected?
Should we find all 4 overlapping matches or only 2 matches consequently (as
other browsers do)?

[yosin_UTC9, 2014-07-28 01:03:58]

LGTM

Add tkent@ for OWNERS review.

[tkent, 2014-07-28 01:26:05]

rslgtm

[tkent, 2014-07-28 01:26:27]

The CQ bit was checked by tkent@chromium.org

[commit-bot: I haz the power, 2014-07-28 01:26:36]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/iceman@yandex-team.ru/422443004/1

[commit-bot: I haz the power, 2014-07-28 02:29:22]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/17273)

[commit-bot: I haz the power, 2014-07-28 03:06:07]

Change committed as 179000

[Vladislav Kaznacheev, 2014-07-28 14:17:27]

A revert of this CL has been created in
https://codereview.chromium.org/424803002/ by kaznacheev@chromium.org.

The reason for reverting is: This broke FindInPageControllerTest.LargePage on
multiple bots (e.g.
http://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%282%29/buil...)

Filed a bug:
https://code.google.com/p/chromium/issues/detail?id=398017.