GitLab

In this first step we split TrustedWebActivityVerifier up into:
- TrustedWebActivityVerifier, which contains the logic for checking
  whether the current url is verified at the appropriate times (eg
  page load, tab switching) and notifying the outside world.
- TwaVerifiedDelegate, which contains the logic specific to TWAs,
  primarily gathering the origins the client app claims it is verified
  for and running Digital Asset Link verification.
- TwaRegistrar, which essentially contains the logic from
  TrustedWebActivtyVerifier#registerClientAppForOrigin

The next steps are:
- Rename TrustedWebActivityVerifier to just Verifier (I didn't do this
  in this CL to make the code review easier).
- Make Verifier agnostic to whether we verify for origins or scopes.
- Moving the TwaRegistrar dependency from Verifier to the
  TWACoordinator.
- Removing the knowledge about the client package name from the
  Verifier - the Verifier shouldn't be the source of truth for this.

Bug: 1017114
Change-Id: If6e508ed99130e0fbbc0c5fd148f65f1a0cae66d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1875750Reviewed-by: Peter Beverloo <peter@chromium.org>
Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Commit-Queue: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709096}