add seedvault as default backup provider and enable backup functionality

[renlord]

prebuilt apk package can be found in https://github.com/renlord/seedvault-prebuilt.

To setup AOSP source tree without repo manually, clone my git repository into external/Seedvault, then build.

Please migrate my repo into Graphene OS to update manifest.

Closes GrapheneOS/os-issue-tracker#25

Also just to elaborate why both Soong/Kati build scripts are used:

Since Android Q introduced the /product partition, the LOCAL_PRODUCT_MODULE := true flag is supposedly meant to allow installation of src files into the /product partitition, but for some reason toggling this flag for modules with the ETC class does not install the ETC modules source files into the product partition when using Kati, hence the usage of Soong Android.bp. Anyways, ideally everything should be migrated to Soong.

[stevesoltys]

Just a heads up, there will likely be more breaking changes in the next release since this is still an alpha version. This would mean backups created with this version cannot be restored in later versions.

Just wanted to make you aware of this in case it impacts the inclusion of Seedvault in GrapheneOS.

[ypid]

Hi @renlord

I am looking into building Seedvault myself for sargo.

Why do you suggest external/Seedvault for the app? It seems that packages/apps/Seedvault is more common and that is also what upstream suggests.

Upstream already provides prebuilds. What is the advantage from yours :) ?

See related discussion over at hashbang/os#41

[renlord]

Upstream already provides prebuilds. What is the advantage from yours :) ?

No advantage whatsoever, but simply re-built for reproducibility reasons.

Why do you suggest external/Seedvault for the app? It seems that packages/apps/Seedvault is more common and that is also what upstream suggests.

AFAIK, prebuilts are included in external/* in Graphene OS and apks built in the AOSP tree is included in packages/apps/*. Since seedvault cant be built in the AOSP tree, i put it in external/* instead.

[ypid]

Thanks for the details! For reference, I will try to automate the building of Seedvault in the Hashbang OS build system.

[renlord]

@thestinger tested on sargo (fresh flashall).
You might want to check if the update works properly for OTA updates.

[ypid]

Thanks @renlord and @chirayudesai!!! I managed to built Seedvault myself and apply this patch set to Hashbang OS and am now testing Seedvault on sargo.