[Cleanup] Remove a duplicated include.

R=asvitkine@chromium.org

Bug: none
Change-Id: Ic61c7eabd922c0c5c542c382ad7fd11ba8750f40
Reviewed-on: https://chromium-review.googlesource.com/818729
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523117}

components/variations/service/variations_service.cc

@@ -34,7 +34,6 @@
 #include "components/prefs/pref_service.h"
 #include "components/variations/pref_names.h"
 #include "components/variations/proto/variations_seed.pb.h"
-#include "components/variations/service/variations_field_trial_creator.h"
 #include "components/variations/variations_seed_processor.h"
 #include "components/variations/variations_seed_simulator.h"
 #include "components/variations/variations_switches.h"