Introduce createMarkup function takes two positions

Introduce createMarkup function takes two positions

This patch introduces |createMarkup()| taking two positions by replace calling
by template class |CreateMarkupAlgorithm<Strategy>::createMark()| to simplify
call sites for improving code health.

This patch is result of collaboration work with hajimehoshi@chromium.org
for selection of web components. After this patch, we are going to
implement another strategies for the composed tree. We've already
prepared that at http://crrev.com/1106433002.

BUG=275851
TEST=n/a; No behavior changes.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197306

[yosin_UTC9, 2015-06-17 09:31:48]

yosin@chromium.org changed reviewers:
+ hajimehoshi@chromium.org

[hajimehoshi, 2015-06-17 09:34:44]

lgtm

[hajimehoshi, 2015-06-17 09:34:47]

The CQ bit was checked by hajimehoshi@chromium.org

[commit-bot: I haz the power, 2015-06-17 09:35:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1187273003/1

[commit-bot: I haz the power, 2015-06-17 09:46:28]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-17 09:46:29]

Try jobs failed on following builders:
  linux_blink_compile_dbg on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_blink_compile_dbg/...)

[yosin_UTC9, 2015-06-18 00:59:18]

The CQ bit was checked by yosin@chromium.org

[yosin_UTC9, 2015-06-18 00:59:19]

The patchset sent to the CQ was uploaded after l-g-t-m from
hajimehoshi@chromium.org
Link to the patchset: https://codereview.chromium.org/1187273003/#ps20001
(title: "2015-06-18T09:58:34")

[commit-bot: I haz the power, 2015-06-18 00:59:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1187273003/20001

[commit-bot: I haz the power, 2015-06-18 02:19:07]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197306