Add default code reviewers into OWNERS

Bug: 33166666
Test: gerrit uploader
Change-Id: Iceb308701d746ca788d5ac7419bcdeb683ca4b73
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..229a641
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1,4 @@
+# Default code reviewers picked from top 3 or more developers.
+# Please update this list if you find better candidates.
+flim@google.com
+essick@google.com