[mojo] Add pickling support for native-only structs

mojo/public/cpp/bindings/tests/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("../../../mojo_application.gni")
 
 source_set("tests") {
   testonly = true
 
   sources = [
     "array_unittest.cc",
     "associated_interface_unittest.cc",
     "binding_callback_unittest.cc",
     "binding_unittest.cc",
     "bounds_checker_unittest.cc",
     "buffer_unittest.cc",
     "callback_unittest.cc",
     "connector_unittest.cc",
     "constant_unittest.cc",
     "container_test_util.cc",
     "equals_unittest.cc",
     "handle_passing_unittest.cc",
     "interface_ptr_unittest.cc",
     "map_unittest.cc",
     "message_queue.cc",
     "message_queue.h",
     "multiplex_router_unittest.cc",
+    "pickle_unittest.cc",
+    "pickled_struct_blink.cc",
+    "pickled_struct_blink.h",
+    "pickled_struct_chromium.cc",
+    "pickled_struct_chromium.h",
     "request_response_unittest.cc",
     "router_test_util.cc",
     "router_test_util.h",
     "router_unittest.cc",
     "sample_service_unittest.cc",
     "serialization_warning_unittest.cc",
     "string_unittest.cc",
     "struct_unittest.cc",
     "type_conversion_unittest.cc",
     "union_unittest.cc",
     "validation_unittest.cc",
   ]
 
   deps = [
     ":mojo_public_bindings_test_utils",
+    "//mojo/common",
     "//mojo/environment:chromium",
     "//mojo/message_pump",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/bindings:callback",
     "//mojo/public/cpp/system",
     "//mojo/public/cpp/test_support:test_utils",
     "//mojo/public/cpp/utility",
     "//mojo/public/interfaces/bindings/tests:test_associated_interfaces",
     "//mojo/public/interfaces/bindings/tests:test_interfaces",
     "//mojo/public/interfaces/bindings/tests:test_interfaces_blink",
@@ skipping 25 matching lines @@
 source_set("mojo_public_bindings_test_utils") {
   sources = [
     "validation_test_input_parser.cc",
     "validation_test_input_parser.h",
   ]
 
   deps = [
     "//mojo/public/c/system",
   ]
 }