Use ConcurrentHashMap directly instead of MapMaker.

PiperOrigin-RevId: 194887386
Change-Id: I9a6ad3f6f8cbdd2c3f878e29db43ad2270100818
diff --git a/java/com/google/gitiles/Renderer.java b/java/com/google/gitiles/Renderer.java
index 12912c2..655b8d2 100644
--- a/java/com/google/gitiles/Renderer.java
+++ b/java/com/google/gitiles/Renderer.java
@@ -21,7 +21,6 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.MapMaker;
 import com.google.common.collect.Maps;
 import com.google.common.hash.Funnels;
 import com.google.common.hash.HashCode;
@@ -37,6 +36,7 @@
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.function.Function;
 import java.util.zip.GZIPOutputStream;
@@ -94,7 +94,7 @@
   protected ImmutableMap<String, URL> templates;
   protected ImmutableMap<String, String> globals;
   private final ConcurrentMap<String, HashCode> hashes =
-      new MapMaker().initialCapacity(SOY_FILENAMES.size()).concurrencyLevel(1).makeMap();
+      new ConcurrentHashMap<>(SOY_FILENAMES.size());
 
   protected Renderer(
       Function<String, URL> resourceMapper,