Fix zip_build to work with output directories generated by ninja.
Fix zip_build to work with output directories generated by ninja.

No known issues with previous land. Just got caught in a revert-pocalypse :)

Previously here: https://chromiumcodereview.appspot.com/11412204


Review URL: https://chromiumcodereview.appspot.com/11416228

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@171000 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build