Don't create multiple WebRange objects for getting selection text.

Don't create multiple WebRange objects for getting selection text.

Editable HTML content is very laggy when it is relatively large. Lag
is caused by creation of WebRange object with given location and offset.
Bigger the editable content and farther the location, the more the lag.

Currently we create WebRange object twice - once for checking presence
of text (plain) and again for fetching actual plain text. It causes the
lag to double the actual value. This patch removes unneccessary double
creation of WebRange.

Sample page and traces showing the lag and improvement with this patch
are attached with the bug.

BUG=396051
R=avi,jochen,yosin

TBR=jochen

TESTS=None

Committed: https://crrev.com/c38791ac14cf1a9b3dd991d9a8cff558e3ce4d00
Cr-Commit-Position: refs/heads/master@{#308261}

[r.kasibhatla, 2014-12-10 11:56:30]

r.kasibhatla@samsung.com changed reviewers:
+ alexmos@chromium.org, tommycli@chromium.org

[r.kasibhatla, 2014-12-10 11:56:41]

PTAL

[r.kasibhatla, 2014-12-10 18:14:16]

r.kasibhatla@samsung.com changed reviewers:
+ avi@chromium.org
- tommycli@chromium.org

[r.kasibhatla, 2014-12-10 18:14:38]

PTAL. Thanks!

[Avi (use Gerrit), 2014-12-10 18:49:50]

On 2014/12/10 18:14:38, r.kasibhatla wrote:
> PTAL. Thanks!

This looks reasonable, but I don't know the Blink types. Find a Blink reviewer
and I will stamp once they're happy.

[r.kasibhatla, 2014-12-11 03:54:04]

r.kasibhatla@samsung.com changed reviewers:
+ jochen@chromium.org
- alexmos@chromium.org

[r.kasibhatla, 2014-12-11 03:54:21]

+ jochen as blink reviewer

[r.kasibhatla, 2014-12-11 13:06:24]

r.kasibhatla@samsung.com changed reviewers:
+ yosin@chromium.org

[r.kasibhatla, 2014-12-11 13:06:59]

+ yosin for blink review.

[r.kasibhatla, 2014-12-12 04:25:43]

On 2014/12/11 13:06:59, r.kasibhatla wrote:
> + yosin for blink review.

Gentle ping!!!
Jochen/Yosin,
Can anyone of you please review the change? Avi is fine with it but wants a
go-ahead by Blink side guy as well.

[jochen (gone - plz use gerrit), 2014-12-12 14:22:26]

lgtm

[Avi (use Gerrit), 2014-12-12 15:13:08]

On 2014/12/12 14:22:26, jochen (slow) wrote:
> lgtm

Jochen is a reviewer, but I'll stamp LGTM anyway.

[r.kasibhatla, 2014-12-13 05:53:10]

The CQ bit was checked by r.kasibhatla@samsung.com

[commit-bot: I haz the power, 2014-12-13 05:53:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/795493003/1

[commit-bot: I haz the power, 2014-12-13 08:15:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-13 08:17:18]

Patchset 1 (id:??) landed as
https://crrev.com/c38791ac14cf1a9b3dd991d9a8cff558e3ce4d00
Cr-Commit-Position: refs/heads/master@{#308261}