Make textDistance() in SelectionController not to create a redundant Range object
Make textDistance() in SelectionController not to create a redundant Range object

This patch makes |textDisatnce()| in "SelectionController.cpp" not to create
a redundant Range object.

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.

Review URL: https://codereview.chromium.org/1190283002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@197456 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk