[signin] Use the new Chrome sync endpoint when signing in to Chrome with DICE.

This CL uses the /signin/chrome/sync Gaia endpoint when signing in to
Chrome when DICE is enabled.

Bug: 789578
Change-Id: Ide40f5b7cc1d3f34f07a482f369d6826c1e2ca29
Reviewed-on: https://chromium-review.googlesource.com/800619
Commit-Queue: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#520599}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: cc55e2950bbb28e91e6d5a5208182bbc8ed7cedd
2 files changed