Update //third_party/protobuf to version 3.

third_party/protobuf/python/google/protobuf/internal/missing_enum_values.proto

Index: third_party/protobuf/python/google/protobuf/internal/missing_enum_values.proto
diff --git a/third_party/protobuf/python/google/protobuf/internal/factory_test1.proto b/third_party/protobuf/python/google/protobuf/internal/missing_enum_values.proto
similarity index 74%
copy from third_party/protobuf/python/google/protobuf/internal/factory_test1.proto
copy to third_party/protobuf/python/google/protobuf/internal/missing_enum_values.proto
index 9f55e037f6e69ff8e76a3f260eff006af1bcce65..1850be5bb7fdb854799efa679db8ca03a06b2823 100644
--- a/third_party/protobuf/python/google/protobuf/internal/factory_test1.proto
+++ b/third_party/protobuf/python/google/protobuf/internal/missing_enum_values.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
@@ -28,28 +28,29 @@
 // (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: matthewtoia@google.com (Matt Toia)
-
+syntax = "proto2";
 
 package google.protobuf.python.internal;
 
-
-enum Factory1Enum {
-  FACTORY_1_VALUE_0 = 0;
-  FACTORY_1_VALUE_1 = 1;
+message TestEnumValues {
+  enum NestedEnum {
+    ZERO = 0;
+    ONE = 1;
+  }
+  optional NestedEnum optional_nested_enum = 1;
+  repeated NestedEnum repeated_nested_enum = 2;
+  repeated NestedEnum packed_nested_enum = 3 [packed = true];
 }
 
-message Factory1Message {
-  optional Factory1Enum factory_1_enum = 1;
-  enum NestedFactory1Enum {
-    NESTED_FACTORY_1_VALUE_0 = 0;
-    NESTED_FACTORY_1_VALUE_1 = 1;
+message TestMissingEnumValues {
+  enum NestedEnum {
+    TWO = 2;
   }
-  optional NestedFactory1Enum nested_factory_1_enum = 2;
-  message NestedFactory1Message {
-    optional string value = 1;
-  }
-  optional NestedFactory1Message nested_factory_1_message = 3;
-  optional int32 scalar_value = 4;
-  repeated string list_value = 5;
+  optional NestedEnum optional_nested_enum = 1;
+  repeated NestedEnum repeated_nested_enum = 2;
+  repeated NestedEnum packed_nested_enum = 3 [packed = true];
+}
+
+message JustString {
+  required string dummy = 1;
 }