Add DIR_METADATA file to //google_update.

Metadata is moved from the OWNERS file into the new DIR_METADATA file.

R=grt@chromium.org

Bug: 1113033
Change-Id: I9becaddab5bf49486fed4eaa3cb0d21d8727e902
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2454691
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Auto-Submit: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815170}

google_update/DIR_METADATA

+# Metadata information for this directory.
+#
+# For more information on DIR_METADATA files, see:
+#   https://source.chromium.org/chromium/infra/infra/+/master:go/src/infra/tools/dirmd/README.md
+#
+# For the schema of this file, see Metadata message:
+#   https://source.chromium.org/chromium/infra/infra/+/master:go/src/infra/tools/dirmd/proto/dir_metadata.proto
+
+monorail {
+  component: "Internals>Installer"
+}
+os: WINDOWS
\ No newline at end of file

google_update/OWNERS

 grt@chromium.org
 robertshield@chromium.org
-
-# COMPONENT: Internals>Installer