Get rid of a redundant createLegacyEditingPosition() call in PositionAlgorithm<Strategy>::upstream()

Get rid of a redundant createLegacyEditingPosition() call in PositionAlgorithm<Strategy>::upstream()

|createLegacyEditingPosition()|, which returns non-legacy editing position if
anchor node returns false for |editingIgnoresContent(node)|, call at L845 is
redundant because it takes a node object, which is |!editingIgnoresContent()|
by if-statement at L835.

This patch replaces a this redundant usage of |createLegacyEditingPosition()| to
|PositionAlgorithm<Strategy>| constructor for improving code health.

This patch is a similar to http://crrev.com/1266413003, which replaces
|createLegacyEditingPosition()| in |PositionAlgorithm<Strategy>::downstream()|.

This patch is a preparation of getting rid of legacy editing position.

BUG=513114
TEST=n/a; no behavior changes

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=199954

[yosin_UTC9, 2015-08-04 05:31:54]

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

[yosin_UTC9, 2015-08-04 05:32:11]

PTAL

[yoichio, 2015-08-04 06:30:48]

"|createLegacyEditingPosition()| call at L845 is redundant because it takes
a node object which is |!editingIgnoresContent(node)| by if-statement at L835."

Please note that this condition enable to call 2nd if-condition in 
createLegacyEditingPosition and other similar refactoring for early
understanding.

[yosin_UTC9, 2015-08-04 06:36:43]

On 2015/08/04 06:30:48, yoichio wrote:
> "|createLegacyEditingPosition()| call at L845 is redundant because it takes
> a node object which is |!editingIgnoresContent(node)| by if-statement at
L835."
> 
> Please note that this condition enable to call 2nd if-condition in 
> createLegacyEditingPosition and other similar refactoring for early
> understanding.

Thanks for suggestion. Update a comment.
PTAL

[yoichio, 2015-08-04 06:58:11]

lgtm

[tkent, 2015-08-04 07:14:18]

The CQ bit was checked by tkent@chromium.org

[tkent, 2015-08-04 07:14:18]

lgtm

[commit-bot: I haz the power, 2015-08-04 07:14:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1262503010/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1262503010/1

[commit-bot: I haz the power, 2015-08-04 07:17:36]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=199954