Ensure that the necessary src/* dependencies are loaded before the viewer, when it's run with gulp server (issue 7448)

[Snuffleupagus]

Fixes #7448.

[yurydelendik]

I wonder if we can just add dependency on pdfjs-web/pdfjs for modules that use polyfilled stuff (and provide comments why we do that).

[Snuffleupagus]

I wonder if we can just add dependency on pdfjs-web/pdfjs for modules that use polyfilled stuff (and provide comments why we do that).

I did consider doing that, but then I figured that since we use Promise in a lot of files, we'd technically need to require the pdfjs-web/pdfjs module in lots of places. Currently there's just one breaking issue (in preferences.js), but that seems more like a happy coincidence, so I figured why not solve this in one place such this issue won't come up somewhere else in the future.

[yurydelendik]

Okay, let's go for your original solution. I'm afraid it might bite us again when we start using different bundler. I'm thinking we shall have something like polyfill module that will export Promise and URL and use these.

[yurydelendik]

Thank you for the patch