Update //third_party/protobuf to version 3.

third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto

Index: third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto
diff --git a/third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto b/third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto
new file mode 100644
index 0000000000000000000000000000000000000000..3b7a004c9e2b1a34bf02afb4e640c9aa4cfd626c
--- /dev/null
+++ b/third_party/protobuf/javanano/src/test/java/com/google/protobuf/nano/unittest_extension_packed_nano.proto
@@ -0,0 +1,29 @@
+syntax = "proto2";
+
+option java_multiple_files = true;
+option java_package = "com.google.protobuf";
+
+import "google/protobuf/nano/unittest_extension_nano.proto";
+
+// Must be compiled separately due to extension number reuse.
+// The reuse is deliberate, for testing wire compatibility.
+
+message PackedExtensions {
+  extend ExtendableMessage {
+    repeated int32    packed_int32    = 10 [ packed = true ];
+    repeated uint32   packed_uint32   = 11 [ packed = true ];
+    repeated sint32   packed_sint32   = 12 [ packed = true ];
+    repeated int64    packed_int64    = 13 [ packed = true ];
+    repeated uint64   packed_uint64   = 14 [ packed = true ];
+    repeated sint64   packed_sint64   = 15 [ packed = true ];
+    repeated fixed32  packed_fixed32  = 16 [ packed = true ];
+    repeated sfixed32 packed_sfixed32 = 17 [ packed = true ];
+    repeated fixed64  packed_fixed64  = 18 [ packed = true ];
+    repeated sfixed64 packed_sfixed64 = 19 [ packed = true ];
+    repeated bool     packed_bool     = 20 [ packed = true ];
+    repeated float    packed_float    = 21 [ packed = true ];
+    repeated double   packed_double   = 22 [ packed = true ];
+    repeated AnEnum   packed_enum     = 23 [ packed = true ];
+    // Non-packable types omitted.
+  }
+}