Find my downloaded files in the browser

[boek]

Part of Meta: #4417

User Story

As a user, I want to be able to easily and quickly find and access my downloaded files from within the browser, so I don’t have to look for them in my Android file system.

Requirements

Populate the downloads UI with a list of files that have been downloaded

(for the v1 minimum, let's copy what fennec does)

Acceptance Criteria

• I can navigate to the Downloads section in my browser
• I can view the list of my COMPLETED downloaded files in the browser
• There is a cap on how long we display a download
• If user deletes a downloaded file from the file system, I no longer see the download in the browser
• I can tap on a downloaded file and open it using the supported Android system app

┆Issue is synchronized with this Jira Task

[nahuhh]

To add to this request

• a ui for the downloader (within menu > library) where you can view current and past downloads, along with the ability to pause/resume/cancel ones that are in progress

[djc]

As a quick fix, even a menu item that sends me to the Files app would be an improvement over the current situation, where downloads basically completely disappear after the initial notification.

[sblatz]

Closing in favor of #4417.

[liuche]

UX will provide icons by next Wednesday, but in the meantime, we can do the default icons. We want to ship with the final icons though.

[kglazko]

This was merged with Nightly feature flags and a QA-needed label has been added.

[liuche]

For QA: the downloads won't persist until this AC issue has landed: mozilla-mobile/android-components#7762

[sflorean]

Testing results on Nightly 8/20:

• I can navigate to the Downloads section in my browser - verified as fixed
• I can view the list of my COMPLETED downloaded files in the browser - partially fixed - failed downloads aren't listed, but if we cancel the download they are displayed in the Downloads section (filed [Bug] Files displayed in the Downloads section after being canceled #13983)
• There is a cap on how long we display a download - do we have here some measurements/extra details?
• If user deletes a downloaded file from the file system, I no longer see the download in the browser - files are still displayed, filed [Bug] Downloaded files are listed in Downloads after being deleted from the device storage #13979
• I can tap on a downloaded file and open it using the supported Android system app - verified as fixed, but for long tap the browser crashes ([Bug] Long press on item in downloads crashes app #13974 is filed).

cc @kglazko

[Amejia481]

For testing this feature:

You will be able to :

1. Navigate to the Downloads section.
2. View the list of my COMPLETED downloaded files.
3. Tap on a downloaded file and open it using the supported Android system app.
4. Downloaded files should be persistent even after the application gets restarted.

To test that 4 (downloads are persistent), after downloaded a file, close the app using the task manager and re open the app, then go to the three dots menu -> Downloads and downloaded files should be shown.

[liuche]

"If user deletes a downloaded file from the file system, I no longer see the download in the browser" is not implemented yet, and will not be present in this build.

[sv-ohorvath]

"If user deletes a downloaded file from the file system, I no longer see the download in the browser" is not implemented yet, and will not be present in this build.

Verified as fixed on Beta 81.1.0 based on the acceptance criteria from #349 (comment), including this: the files deleted from the system file manager will be removed from the browser Downloads list as well (fixed in #13979).