[Extensions] Add unpacked location type for extension features

This CL adds a new "unpacked" value which could be specied under the
"location" key for extension features. APIs/events specified as
"unpacked" will only be available for unpacked and command line
extensions.

This change was motivated by the
declarativeNetRequest.OnRuleMatchedDebug event which should only be
available for unpacked extensions.

Bug: 1017934
Change-Id: Iafe0a64160dc4ca083bcf58393aba94a87bfd3a4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1892212
Commit-Queue: Kelvin Jiang <[email protected]>
Reviewed-by: Devlin <[email protected]>
Reviewed-by: Karan Bhatia <[email protected]>
Cr-Commit-Position: refs/heads/master@{#711807}
5 files changed