Removed unnecessary SubtreeStyleChange for incrementalAttr.

Changing the incremental attribute on input type=search does not affect
style unless there are attribute selectors for it which will be handled
other places.

R=tkent@chromium.org
BUG=557440

Review URL: https://codereview.chromium.org/1478953004

Cr-Commit-Position: refs/heads/master@{#362076}
3 files changed