Make 'License' field in third-party metadata required

This will simplify the addition of a tool to check licenses for the purpose of
the Android WebView build.

See also

Also adds other missing fields to these README.chromium files as required by
presubmit checks and fixes a regex used to enforce this.


Review URL:

git-svn-id: 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
1 file changed
tree: 3216b33b46aa96cc2e6b4d2e6ebefedb87f47767
  1. README.chromium