Upstream Chrome on iOS source code [11/11].

Upstream all BUILD.gn changes to enable compilation of the code
that has been upstreamed by the previous ten CLs and changes to
browser_state_keyed_service_factories.mm to use the new factory.

Update the default provider factory to use chromium provider (it
will be merged with ChromeBrowserProvider eventually).

BUG=653086
R=pinkerton@chromium.org, rohitrao@chromium.org

Review-Url: https://codereview.chromium.org/2589843002 .
Cr-Commit-Position: refs/heads/master@{#439492}
94 files changed