Cannot browse to file:// URIs

[theres-waldo]

Steps to reproduce

1. Make sure Reference Browser has the "Storage" permission
2. Navigate to file:///storage/emulated/0/Documents.

Expected behavior

• The browser displays a list of local files in the Documents folder and allows you to open them.

Actual behavior

• The browser searches Google for "file:///storage/emulated/0/Documents".

Device information

• Android device: Moto G5
• Reference Browser version:

There is a corresponding bug for Fenix at mozilla-mobile/fenix#4049 which is under active discussion, but I think reference-browser should go ahead and allow this in the meantime, for development purposes.

It's is a significant productivity hit for mobile Gecko development to not be able to load local testcases in a GeckoView-based browser (besides GVE which lacks many features).