Frontend desktop support for running DiscoverAssets on page refresh

[nvonpentz]

Background

Backend support issue - #25820.

The backend will provide a DiscoverAssetsOnAllSupportedChains API to the frontend that it can call to run the discover assets logic when the user reloads the wallet UI. The API will look like this with with no callback:

interface BraveWalletService {
  DiscoverAssetsOnAllSupportedChains();
}

Upon completion/failure, the backend will emit an event for each chain.

interface BraveWalletServiceObserver {
  // Fired when a discovered asset query completes
  OnDiscoverAssetsCompleted(array<BlockchainToken> discovered_assets);
};

If it's useful for the frontend, the backend can also emit an event when discovery logic completes for all supported chains.

Spec

More input needed to determine the the specifics, but the frontend implementation should be something like this --

1. Call this API when appropriate (on-refresh)
2. Display some UI to the user indicating that the asset discovery has running
3. Indicate to the user when that has completed

[jamesmudgett]

We should use one single row "loading skeleton" at the bottom of any list on load and until the final completion/failure call has been executed.

[nvonpentz]

@jamesmudgett should the OnDiscoverAssetsCompleted event the frontend receives contain data on whether the calls succeeded or failed, or just that they are complete?

[srirambv]

Verification passed on

Brave	1.48.141 Chromium: 109.0.5414.119 (Official Build) beta (64-bit)
Revision	772095164c7d5d4e73160f858efed3b5e87eca83-refs/branch-heads/5414@{#1458}
OS	Linux

• Verified steps from brave/brave-core#16329
• Verified loading skeleton is shown at the bottom of the asset list on both portfolio page and account page

26547.mp4

---

Verification passed on

Brave	1.48.141 Chromium: 109.0.5414.119 (Official Build) beta (64-bit)
Revision	772095164c7d5d4e73160f858efed3b5e87eca83-refs/branch-heads/5414@{#1458}
OS	Windows 11 Version 22H2 (Build 22621.755)

• Verified steps from brave/brave-core#16329
• Verified loading skeleton is shown at the bottom of the asset list on both portfolio page and account page

26547.mp4

---

Verification passed on

Brave	1.48.141 Chromium: 109.0.5414.119 (Official Build) beta (arm64)
Revision	772095164c7d5d4e73160f858efed3b5e87eca83-refs/branch-heads/5414@{#1458}
OS	macOS Version 13.0 (Build 22A380)

• Verified steps from brave/brave-core#16329
• Verified loading skeleton is shown at the bottom of the asset list on both portfolio page and account page

26547.mov