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

Review URL: https://codereview.chromium.org/1262503010

git-svn-id: svn://svn.chromium.org/blink/trunk@199954 bbb929c8-8fbe-4397-9dbb-9b2b20218538
1 file changed