Revert 95815 - Make extension file URL access opt-in.

Revert 95815 - Make extension file URL access opt-in.

This corrects an issue causing file URL access to default on for <all_urls> and file:/// permissions. We also revert all extension's "allow file access" flags to false since we can't distinguish between extensions that were installed with the bug present and those where the user clicked allow file access. Unpacked extensions will now have opt-in file access as well.

BUG=91577
TEST=ExtensionServiceTest.DefaultFileAccess

Review URL: http://codereview.chromium.org/7574017

TBR=jstritar@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=95820