Don't re-initialize mojo::core in gaia unittests

mojo::core::Init() should be called once per process, not once per test.
run_all_unittests.cc happens to already define a test launcher that
calls mojo::core::Init(), so if we use that instead of the base
launcher, we can get rid of re-initialization in test fixtures.

Bug: 869281
Change-Id: Ieb96cbe580f5f1750d7f61693c288bb578cb63b0
Reviewed-on: https://chromium-review.googlesource.com/1155595
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584501}
8 files changed