Update IdentityManager to own GaiaCookieManagerService.

With this change, GaiaCookieManagerService is now constructed only when
creating an IdentityManager, eliminating the need for
GaiaCookieManagerService factories.

Bug: 939372
Change-Id: I14463bc6b71b8bf135cceba0159d440fe7872dea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1532226
Commit-Queue: Lowell Manners <lowell@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#644232}
23 files changed