Add specific OWNERS for google_tld_list.h

Bug: 
Change-Id: I73558b750b22f68f0048babd8e8960d851255753
Reviewed-on: https://chromium-review.googlesource.com/801661Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Martin Šrámek <msramek@chromium.org>
Commit-Queue: Maria Khomenko <mariakhomenko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520776}

components/google/core/browser/OWNERS

+per-file google_tld_list.h=mariakhomenko@chromium.org
+per-file google_tld_list.h=msramek@chromium.org
+