Add default code reviewers into OWNERS

Bug: 33166666
Test: gerrit uploader
Change-Id: Icacb723e4325a5714e0870292c5a22b0886e0b5c
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..679960d
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1,6 @@
+# Default code reviewers picked from top 3 or more developers.
+# Please update this list if you find better candidates.
+twasilczyk@google.com
+sdai@google.com
+ajchen@google.com
+arnaudberry@google.com