Add an owners file for dexpreopt files.

Test: N/A
Change-Id: I3d14a3cb6f0f5f8f5c0a7266285d4b8917922240
diff --git a/java/OWNERS b/java/OWNERS
new file mode 100644
index 0000000..d68a5b0
--- /dev/null
+++ b/java/OWNERS
@@ -0,0 +1 @@
+per-file dexpreopt.go = ngeoffray@google.com,calin@google.com,mathieuc@google.com