Remove integration test dependencies on FakeGaiaCookieManagerService.

Instead of creating a FakeGaiaCookieManagerService, we now set mock
responses using the TestURLLoaderFactory that already existed in
SyncTest.

As part of this change, the helpers that need access to the
TestURLLoaderFactory in SyncTest were moved from
secondary_account_helper to a test class which inherits from SyncTest.

Removing this dependency will make it easier to eliminate FakeGCMS
entirely:
http://doc/1t0ZtuV7h-znzdItFgBW0aKPscAwWXIBuNZnNlEGgi7g#heading=h.7dt3rezdvj2u

Bug: 907782
Change-Id: Id60b56ecc76bf0d4bbe0089deec53e0d4225d4f0
Reviewed-on: https://chromium-review.googlesource.com/c/1396148
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: Colin Blundell <blundell@chromium.org>
Commit-Queue: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621200}
12 files changed