Introduce Position::nodeAsRangeLastNode

Introduce Position::nodeAsRangeLastNode

This CL introduces Position::nodeAsRangeLastNode which returns a
previous node of nodeAsRangePastLastNode. This function will be used at
VisibleSelection for the composed tree (crrev.com/1194833002).

This CL also adds tests for Position.

This CL is a split of crrev.com/1194833002.

This patch is result of collaboration work with yosin@chromium.org
for selection of web components. We've already prepared the new
node-traversal usages at crrev.com/1188063002.

BUG=275851
TEST=webkit_unit_tests --gtest_filter=PositionTest.*

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197554

[hajimehoshi, 2015-06-19 10:08:54]

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

[hajimehoshi, 2015-06-19 10:08:55]

PTAL

[yosin_UTC9, 2015-06-19 11:59:01]

Code changes looks OK.

https://codereview.chromium.org/1190303002/diff/1/Source/core/dom/PositionTes...
File Source/core/dom/PositionTest.cpp (right):

https://codereview.chromium.org/1190303002/diff/1/Source/core/dom/PositionTes...
Source/core/dom/PositionTest.cpp:12: #include "wtf/RefPtr.h"
Please include "core/testing/CoreTestHelpers.h", it prints |Position| in human
readable format and helps us debugging failed tests.

[tkent, 2015-06-22 01:03:25]

lgtm

https://codereview.chromium.org/1190303002/diff/1/Source/core/dom/PositionTes...
File Source/core/dom/PositionTest.cpp (right):

https://codereview.chromium.org/1190303002/diff/1/Source/core/dom/PositionTes...
Source/core/dom/PositionTest.cpp:125: 
nit: this blank line is unnecessary.

[hajimehoshi, 2015-06-22 04:09:08]

Thank you!

https://codereview.chromium.org/1190303002/diff/1/Source/core/dom/PositionTes...
File Source/core/dom/PositionTest.cpp (right):

https://codereview.chromium.org/1190303002/diff/1/Source/core/dom/PositionTes...
Source/core/dom/PositionTest.cpp:12: #include "wtf/RefPtr.h"
On 2015/06/19 11:59:00, Yosi_UTC9 wrote:
> Please include "core/testing/CoreTestHelpers.h", it prints |Position| in human
> readable format and helps us debugging failed tests.

Done.

https://codereview.chromium.org/1190303002/diff/1/Source/core/dom/PositionTes...
Source/core/dom/PositionTest.cpp:125: 
On 2015/06/22 01:03:25, tkent wrote:
> nit: this blank line is unnecessary.

Done.

[hajimehoshi, 2015-06-22 04:09:12]

The CQ bit was checked by hajimehoshi@chromium.org

[hajimehoshi, 2015-06-22 04:09:12]

The patchset sent to the CQ was uploaded after l-g-t-m from tkent@chromium.org
Link to the patchset: https://codereview.chromium.org/1190303002/#ps20001
(title: "reviews")

[commit-bot: I haz the power, 2015-06-22 04:09:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1190303002/20001

[commit-bot: I haz the power, 2015-06-22 05:25:42]

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

[commit-bot: I haz the power, 2015-06-22 05:25:42]

Try jobs failed on following builders:
  mac_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/mac_blink_rel/builds/59992)

[hajimehoshi, 2015-06-22 05:26:17]

The CQ bit was checked by hajimehoshi@chromium.org

[commit-bot: I haz the power, 2015-06-22 05:26:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1190303002/20001

[commit-bot: I haz the power, 2015-06-22 06:26:27]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197554