drawFocusRing() function in CRC2D draws invalid focus ring.

The function draws a focus ring around the current default path or the given path if the given element is focused.
Currently, the focus ring is drawn incorrectly because it is larger than the given path region.
To solve this problem, we should add focus ring width to dirty rect.

BUG=352976

Review URL: https://codereview.chromium.org/200283003

git-svn-id: svn://svn.chromium.org/blink/trunk@169913 bbb929c8-8fbe-4397-9dbb-9b2b20218538