[signin] Do not build MultableProfileOAuth2TokenService delegate on ChromeOS and iOS

This is a reland of
https://chromium-review.googlesource.com/c/chromium/src/+/1930818

Change-Id: I974c44b0cbffc5621f1fd9b0c9f7358061f907a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1932801
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Commit-Queue: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718652}
5 files changed