Remove 'chrome-extension://*' prefix from URL bar

[darkdh]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Ran git rebase -i to squash commits if needed.

fix #2534

[bbondy]

Thanks for the patch, we should go with the more generalized startsWith then substring exact check though because there are some extension URLs we don't want to truncate. One example is if you enable dashlane it will open a sign in chrome extension page and make available a dashlane preferences page which is a chrome-extension URL.

[darkdh]

You are right. We cannot always truncate all the chrome-extension URL.
888c5fa will be more flexible.

[diracdeltas]

This should probably only happen if PDFJS is enabled in prefs. Otherwise LGTM!

[darkdh]

Thanks @diracdeltas. Checking prefs is in bba8abf.

[diracdeltas]

lgtm! please squash commits and i'll merge