Add virtual GetJavaObject on profile_oauth2_token_service_delegate

This makes GetJavaObject from oauth2_token_service_delegate_android
virtual and defined on the base class,
profile_oauth2_token_service_delegate. It is a prerequisite to the
internalization of oauth2_token_service_delegate_android, as
IdentityManager.java will need a reference on OAuth2TokenService.java on
construction. This also avoids the use of a static_cast to
oauth2_token_service_delegate_android in Identity_manager that is not
always valid.

details here:
  https://docs.google.com/document/d/1_ks5kg3qr6TVq7NT6MFg6lh5Yiv-1lic6Rsd9nu5ubI/edit?usp=sharing


Bug: 934688
Change-Id: Ie0c6d3e004dadd36fe21147a55616d782f2939dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1748892
Commit-Queue: Pâris Meuleman <pmeuleman@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695970}
6 files changed