VisibilityCache: Replace lambda with method reference

Change-Id: I09d374436fdb4da3e2bf5e9226df6dc3bf301ff6

java/com/google/gitiles/VisibilityCache.java

diff --git a/java/com/google/gitiles/VisibilityCache.java b/java/com/google/gitiles/VisibilityCache.java
index 4305d1d..49743d9 100644
--- a/java/com/google/gitiles/VisibilityCache.java
+++ b/java/com/google/gitiles/VisibilityCache.java
@@ -170,7 +170,7 @@
         || isReachableFromRefs("heads", walk, commit, refDb.getRefsByPrefix(R_HEADS).stream())
         || isReachableFromRefs("tags", walk, commit, refDb.getRefsByPrefix(R_TAGS).stream())
         || isReachableFromRefs(
-            "other", walk, commit, refDb.getRefs().stream().filter(r -> otherRefs(r)));
+            "other", walk, commit, refDb.getRefs().stream().filter(VisibilityCache::otherRefs));
   }
 
   private static boolean refStartsWith(Ref ref, String prefix) {