Fix license metadata for ppapi

Currently, the license file mentions only the BSD license, but some of the code
in lib/ seems to use an MIT license.

Also include this directory in the list of extra directories scanned by the
license tool.

BUG=138921


Review URL: https://chromiumcodereview.appspot.com/10828117

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149700 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed