Update //third_party/protobuf to version 3.

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/src/google/protobuf/unittest_mset.proto b/third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/MapFactories.java
similarity index 58%
copy from third_party/protobuf/src/google/protobuf/unittest_mset.proto
copy to third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/MapFactories.java
index 3497f09fa6d41b7b38357e7f2610dfb5c087d3e4..98fa4877bc404451ff9d36483f23f7ac0a059f4b 100644
--- a/third_party/protobuf/src/google/protobuf/unittest_mset.proto
+++ b/third_party/protobuf/javanano/src/main/java/com/google/protobuf/nano/MapFactories.java
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// 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
@@ -28,45 +28,40 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Author: kenton@google.com (Kenton Varda)
-//  Based on original Protocol Buffers design by
-//  Sanjay Ghemawat, Jeff Dean, and others.
-//
-// This file contains messages for testing message_set_wire_format.
-
-package protobuf_unittest;
+package com.google.protobuf.nano;
 
-option optimize_for = SPEED;
+import java.util.HashMap;
+import java.util.Map;
 
-// A message with message_set_wire_format.
-message TestMessageSet {
-  option message_set_wire_format = true;
-  extensions 4 to max;
-}
-
-message TestMessageSetContainer {
-  optional TestMessageSet message_set = 1;
-}
+/**
+ * Utility class for maps support.
+ */
+public final class MapFactories {
+  public static interface MapFactory {
+    <K, V> Map<K, V> forMap(Map<K, V> oldMap);
+  }
 
-message TestMessageSetExtension1 {
-  extend TestMessageSet {
-    optional TestMessageSetExtension1 message_set_extension = 1545008;
+  // 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;
   }
-  optional int32 i = 15;
-}
 
-message TestMessageSetExtension2 {
-  extend TestMessageSet {
-    optional TestMessageSetExtension2 message_set_extension = 1547769;
+  public static MapFactory getMapFactory() {
+    return mapFactory;
   }
-  optional string str = 25;
-}
 
-// MessageSet wire format is equivalent to this.
-message RawMessageSet {
-  repeated group Item = 1 {
-    required int32 type_id = 2;
-    required bytes message = 3;
+  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() {}
+}