Get rid of unused enum member DoNotUpdateAppearance from FrameSelection::SetSelectionOption

This patch gets rid of unused enum member |DoNotUpdateAppearance| from
|FrameSelection::SetSelectionOption| for improving code health.

The usage of |DoNotUpdateAppearance| in |SpellCheckerTest| doesn't affect what
the test verified.

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

Review-Url: https://codereview.chromium.org/2703403002
Cr-Commit-Position: refs/heads/master@{#451868}
3 files changed