Check PrefixSet results for sorting and duplication.

Check whether PrefixSet::GetPrefixes() returns results that are
unsorted or contain duplicates, and indicate how many items are unique
to the restored vector (or aren't in the restored vector).

BUG=71832
TEST=histograms

Review URL: http://codereview.chromium.org/6711054

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@78807 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed