Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/unittest_lite.proto

Index: third_party/protobuf/src/google/protobuf/unittest_lite.proto
diff --git a/third_party/protobuf/src/google/protobuf/unittest_lite.proto b/third_party/protobuf/src/google/protobuf/unittest_lite.proto
index a1764aac8dbdaca6982e8eac11794440aac3a63a..662c0e461f1a501c41cba9d50fe11c0131947f61 100644
--- a/third_party/protobuf/src/google/protobuf/unittest_lite.proto
+++ b/third_party/protobuf/src/google/protobuf/unittest_lite.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
@@ -32,6 +32,7 @@
 //
 // This is like unittest.proto but with optimize_for = LITE_RUNTIME.
 
+syntax = "proto2";
 package protobuf_unittest;
 
 import "google/protobuf/unittest_import_lite.proto";
@@ -151,6 +152,14 @@ message TestAllTypesLite {
 
   optional string default_string_piece = 84 [ctype=STRING_PIECE,default="abc"];
   optional string default_cord = 85 [ctype=CORD,default="123"];
+
+  // For oneof test
+  oneof oneof_field {
+    uint32 oneof_uint32 = 111;
+    NestedMessage oneof_nested_message = 112;
+    string oneof_string = 113;
+    bytes oneof_bytes = 114;
+  }
 }
 
 message ForeignMessageLite {
@@ -293,6 +302,12 @@ extend TestAllExtensionsLite {
   optional string default_string_piece_extension_lite = 84 [ctype=STRING_PIECE,
                                                             default="abc"];
   optional string default_cord_extension_lite = 85 [ctype=CORD, default="123"];
+
+  // For oneof test
+  optional uint32 oneof_uint32_extension_lite = 111;
+  optional TestAllTypesLite.NestedMessage oneof_nested_message_extension_lite = 112;
+  optional string oneof_string_extension_lite = 113;
+  optional bytes oneof_bytes_extension_lite = 114;
 }
 
 message TestPackedExtensionsLite {
@@ -358,3 +373,13 @@ message TestParsingMergeLite {
     repeated TestAllTypesLite repeated_ext = 1001;
   }
 }
+
+// TestEmptyMessageLite is used to test unknown fields support in lite mode.
+message TestEmptyMessageLite{
+}
+
+// Like above, but declare all field numbers as potential extensions.  No
+// actual extensions should ever be defined for this type.
+message TestEmptyMessageWithExtensionsLite {
+  extensions 1 to max;
+}