WebView: propose myself as OWNER

No change to logic, only OWNERS file.

I'm proposing myself as a code owner for frameworks/base/.../webkit. I'm
already an owner for our AndroidX APIs, so I think it's reasonable and
convenient to also be an owner for our framework APIs too.

Bug: None
Test: None
Change-Id: I602ad9fb88017c68e7e58cb29093fa29d80c1fc4