[WV] Adding WebView boundary interface for asyncShouldInterceptRequest

See the expected interfaces at go/chips-android-apis-webview.

Low-Coverage-Reason: HARD_TO_TEST Generally the boundary interfaces have no direct test coverage. Instead, end to end, AndroidX, and CTS tests provide coverage not tracked by infra here.
Test: N/A
Bug: 364913812
Change-Id: I30af8a1469a5afaf88a32f4d34df5b0d13c74dc3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6249600
Auto-Submit: Adam Walls <avvall@chromium.org>
Reviewed-by: Tomasz Wiszkowski <ender@google.com>
Commit-Queue: Tomasz Wiszkowski <ender@google.com>
Reviewed-by: Richard (Torne) Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1426601}