Update //third_party/protobuf to version 3.

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

Index: third_party/protobuf/src/google/protobuf/util/internal/testdata/struct.proto
diff --git a/third_party/protobuf/src/google/protobuf/unittest_import_public_lite.proto b/third_party/protobuf/src/google/protobuf/util/internal/testdata/struct.proto
similarity index 81%
copy from third_party/protobuf/src/google/protobuf/unittest_import_public_lite.proto
copy to third_party/protobuf/src/google/protobuf/util/internal/testdata/struct.proto
index d077563cbd84d7be6daddec3f553cb564f23da0a..c15aba0d6d9881b8963a0353cdd1e0aa0b4adc11 100644
--- a/third_party/protobuf/src/google/protobuf/unittest_import_public_lite.proto
+++ b/third_party/protobuf/src/google/protobuf/util/internal/testdata/struct.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
@@ -28,15 +28,18 @@
 // (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)
+// Proto to test proto3 struct.
+syntax = "proto3";
 
+package google.protobuf.testing.structs;
+option java_package = "com.google.protobuf.testing.structs";
 
-package protobuf_unittest_import;
+import "google/protobuf/struct.proto";
 
-option optimize_for = LITE_RUNTIME;
-
-option java_package = "com.google.protobuf";
+message StructType {
+  google.protobuf.Struct object = 1;
+}
 
-message PublicImportMessageLite {
-  optional int32 e = 1;
+service TestService {
+  rpc Call(StructType) returns (StructType);
 }