Fix b/16139028 Part2: Do not feed docids that are too long.

Examination of customer log files showed frequent exceptions thrown
from WindowsAclFileAttributesView.getFileSecurity() claiming that
"The filename, directory name, or volume label syntax is incorrect."
As it turned out, all these pathnames exceeded the maximum pathname
length of 260 characters. The too-long pathnames occur when we prepend
the UNC server + share syntax to the local pathname.


This change avoids feeding docids that are too long. The windows
version of newDocId() now throws IllegalArgumentException if the
supplied pathname is too long.

Code Review:
3 files changed