Eliminate oauth2_token_service_observer_bridge*

This is no longer used for the iOS build and can be safely removed.

Bug: 921615
Change-Id: Iccc65ed6ce63f081f0a76d9d3d59786c898cdc7d
Reviewed-on: https://chromium-review.googlesource.com/c/1414891
Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Commit-Queue: Mario Sanchez Prada <mario@igalia.com>
Cr-Commit-Position: refs/heads/master@{#623207}
3 files changed