DO NOT MERGE Add webkit plumbing for file origin policy

Bug: 6212665

This is a cherry-pick from master branch. sha:
     0ea6dad65eb77f9347a59704b1f8a019cfc9e01f

(cherry picked from commit 57633fd9f863f5e1e4ce8fab0eb05ddb535e1be6)

Change-Id: I9c2fa81aa3e16d39ed79d171ae09b1f99d9e7082
1 file changed