Mojo C++ bindings: disallow copy and assign for generated classes when necessary.

mojo/public/interfaces/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("../../../tools/bindings/mojom.gni")
 
 mojom("test_interfaces") {
   testonly = true
   sources = [
     "math_calculator.mojom",
@@ skipping 13 matching lines @@
     "test_structs.mojom",
     "test_sync_methods.mojom",
     "validation_test_interfaces.mojom",
   ]
   public_deps = [
     ":test_mojom_import",
     ":test_mojom_import2",
   ]
 }
 
+component("test_export_component") {
+  testonly = true
+  deps = [
+    ":test_export",
+  ]
+}
+
+mojom("test_export") {
+  testonly = true
+  sources = [
+    "test_export.mojom",
+  ]
+  export_class_attribute = "MOJO_TEST_EXPORT"
+  export_define = "MOJO_TEST_IMPLEMENTATION=1"
+  export_header = "mojo/public/cpp/bindings/tests/mojo_test_export.h"
+}
+
 mojom("test_mojom_import") {
   testonly = true
   sources = [
     "sample_import.mojom",
   ]
 }
 
 mojom("test_mojom_import_wrapper") {
   testonly = true
   public_deps = [
@@ skipping 65 matching lines @@
   ]
 }
 
 mojom("test_no_sources") {
   testonly = true
 
   public_deps = [
     ":test_interfaces",
   ]
 }