[Fuchsia] Don't InitializeViewTokenAndPresentView() under 'headless'.

Tests use //ui/aura/test/test_screen.cc, which under Fuchsia calls
InitializeViewTokenAndPresentView(), which creates a token and invokes
fuchsia.ui.policy.Presenter.Present(). This may cause the presenter
service to be started, if not already running, which may lead to
crashes or logspam.

Bug: DX-1801
Change-Id: I65f1ff5e86557d236de8df58cea351b265627a4b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1729514
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Sergey Ulanov <sergeyu@chromium.org>
Auto-Submit: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683664}
2 files changed