avm1: Partially implement FileReference

[CUB3D]

This partially implements flash.net.FileReference (#307), based of @hatal175's initial work on implementing browse from around 2021.

Implements:

• browse
  • The file picker is provided via the AsyncFileDialog crate on all platforms.
• download
  • Does not support authentication, which is apparently supported in the Flash Player browser Plugin.
  • Does not report intermediate progress to listeners, a single onProgress callback is ran after the download has completed
• upload
  • Does not support authentication.
  • Does not report intermediate progress.

Does not implement:

• cancel
  • Neither downloads, nor uploads can be canceled whilst they are in progress

In addition to adding the above, the test harnesses have been updated to allow simulating successful / failed requests, via a new TestNavigatorBackend and dialog interactions can be simulated via the TestUiBackend allowing regression tests for the new functionality.

On web platforms, the ability to upload is dependent on cors configuration for the destination which may still prevent some content from working.

Whilst implementing this, care has been taken to match the ordering for the callbacks that Flash Player invokes in erroneous conditions, however there may still be some differences in some scenarios. To facilitate this, NavigatorBackend::fetch has been updated to return a FetchError containing error details.

Remaining:

• Appease clippy
• Clean up some todos
• Testing harness changes
• Download tests
• Upload tests
• Browse tests
• dates should actually be Dates
• Correct confusing callbacks
• Update web UI backend
• Test on other platforms
• rebase
• Support saving on web
• Update to rfd 0.12.1 (see Fix file-handle-inner on wasm PolyMeilex/rfd#153)

[Herschel]

Thanks for the patience here, this one's a little chunky but I'll take some time to review it this week

[ousia]

Since save_file on WASM is now supported with PolyMeilex/rfd#134 and included in its latest release, it would be great to have download for other than desktop.

Many thanks for your help, @CUB3D.

[BarbourSmith]

Howdy y'all!

I have a flash project that I would like to revive and it works ALMOST perfectly in Ruffle...but it relies on the file dialog 😞 ...We're so close, but so far.

Would anyone be interested in reviving this pull request and seeing it across the finish line? I would be happy to spend some money to make it worth your time.

If it impacts your decision the flash project we are trying to revive is an open source project and it is going to be used by the community of another open source project .

The SWF file that we are hoping to run again is here:

partkam.swf.zip

It's browser based so downloading with WASM would be important.

Thanks for all the awesome work! Let me know if I can make it worth someone's while to get this PR wrapped up and merged in.

❤️ ❤️

[Dinnerbone]

LGTM with one minor fixup

[Lord-McSweeney]

context.avm_trace is used several times in loader.rs- should those be tracing::info! instead? Or is there a reason they're avm_trace?

[BarbourSmith]

Thank you so much for doing this! Is adding support for ActionScript3 on the road map at all? Is there anything that I could do to help get it on the road map?