Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/MapFactories.java

Index: third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/MapFactories.java
diff --git a/third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/MapFactories.java b/third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/MapFactories.java
deleted file mode 100644
index 98fa4877bc404451ff9d36483f23f7ac0a059f4b..0000000000000000000000000000000000000000
--- a/third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/MapFactories.java
+++ /dev/null
@@ -1,67 +0,0 @@
-// Protocol Buffers - Google's data interchange format
-// Copyright 2013 Google Inc.  All rights reserved.
-// https://developers.google.com/protocol-buffers/
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-package com.google.protobuf.nano;
-
-import java.util.HashMap;
-import java.util.Map;
-
-/**
- * Utility class for maps support.
- */
-public final class MapFactories {
-  public static interface MapFactory {
-    <K, V> Map<K, V> forMap(Map<K, V> oldMap);
-  }
-
-  // NOTE(liujisi): The factory setter is temporarily marked as package private.
-  // The way to provide customized implementations of maps for different
-  // platforms are still under discussion.  Mark it as private to avoid exposing
-  // the API in proto3 alpha release.
-  /* public */ static void setMapFactory(MapFactory newMapFactory) {
-    mapFactory = newMapFactory;
-  }
-
-  public static MapFactory getMapFactory() {
-    return mapFactory;
-  }
-
-  private static class DefaultMapFactory implements MapFactory {
-    public <K, V> Map<K, V> forMap(Map<K, V> oldMap) {
-      if (oldMap == null) {
-        return new HashMap<K, V>();
-      }
-      return oldMap;
-    }
-  }
-  private static volatile MapFactory mapFactory = new DefaultMapFactory();
-
-  private MapFactories() {}
-}