Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/util/internal/testdata/default_value_test.proto

Index: third_party/protobuf/src/google/protobuf/util/internal/testdata/default_value_test.proto
diff --git a/third_party/protobuf/src/google/protobuf/unittest_import_public.proto b/third_party/protobuf/src/google/protobuf/util/internal/testdata/default_value_test.proto
similarity index 75%
copy from third_party/protobuf/src/google/protobuf/unittest_import_public.proto
copy to third_party/protobuf/src/google/protobuf/util/internal/testdata/default_value_test.proto
index ea5d1b13fea77a432cecc0980664c020159d108a..932883410e2c7e60ba16818cdfffd867cfce7788 100644
--- a/third_party/protobuf/src/google/protobuf/unittest_import_public.proto
+++ b/third_party/protobuf/src/google/protobuf/util/internal/testdata/default_value_test.proto
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// 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
@@ -28,13 +28,26 @@
 // (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: liujisi@google.com (Pherl Liu)
+syntax = "proto3";
 
+package google.protobuf.testing;
 
-package protobuf_unittest_import;
+message DefaultValueTest {
+  double double_value = 1;
+  repeated double repeated_double = 2;
+  float float_value = 3;
+  int64 int64_value = 5;
+  uint64 uint64_value = 7;
+  int32 int32_value = 9;
+  uint32 uint32_value = 11;
+  bool bool_value = 13;
+  string string_value = 15;
+  bytes bytes_value = 17 [ctype = CORD];
 
-option java_package = "com.google.protobuf.test";
-
-message PublicImportMessage {
-  optional int32 e = 1;
+  enum EnumDefault {
+    ENUM_FIRST = 0;
+    ENUM_SECOND = 1;
+    ENUM_THIRD = 2;
+  }
+  EnumDefault enum_value = 18;
 }