Windows: Make file_util::Delete("c:\\foo_dir", false) work correctly. Add more unit tests for Delete.

BUG=42374
TEST=included
Review URL: http://codereview.chromium.org/1763008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@46725 0039d316-1c4b-4281-b951-d872f2087c98
9 files changed