[chromium] Use lipo(1) rather than file(1) to list library architectures.
https://bugs.webkit.org/show_bug.cgi?id=111147

Parsing file(1) output can be fragile; this patch replaces a use of file(1) to get
the architecture list of a library with an invocation of lipo(1), which should be more
stable.

Reviewed by Nico Weber.

No new tests, since adjust_visibility.sh doesn't have a test.

* WebCore.gyp/mac/adjust_visibility.sh:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145574 268f45cc-cd09-0410-ab3c-d52691b4dbfc