[metrics] Add alexilin@ to profile histograms owners

Change-Id: Ie26fda72af2d7c5d675619c43fa453f9d045e177
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2568282
Auto-Submit: Alex Ilin <alexilin@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833113}

tools/metrics/histograms/histograms_xml/profile/OWNERS

+# Prefer chromium-metrics-reviews@google.com instead.
+# Use the following owners only if:
+#  - The reviewer is available for review.
+#  - You work in the same area as them.
+#  - They are already a good reviewer for the non-metrics part of the CL.
+# See tools/metrics/histograms/histograms_xml/OWNERS for details.
+alexilin@chromium.org