Mojo C++ bindings: provide data view for all object types.

mojo/public/interfaces/bindings/tests/test_data_view.mojom

+// Copyright 2016 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.
+
+module mojo.test.data_view;
+
+enum TestEnum {
+  VALUE_0,
+  VALUE_1
+};
+
+interface TestInterface {
+  [Sync]
+  Echo(int32 value) => (int32 out_value);
+};
+
+struct NestedStruct {
+  int32 f_int32;
+};
+
+[Native]
+struct TestNativeStruct;
+
+union TestUnion {
+  bool f_bool;
+  int32 f_int32;
+};
+
+struct TestStruct {
+  string f_string;
+  NestedStruct? f_struct;
+  TestNativeStruct? f_native_struct;
+  array<bool> f_bool_array;
+  array<int32> f_int32_array;
+  array<TestEnum> f_enum_array;
+  array<TestInterface> f_interface_array;
+  array<array<int32>> f_nested_array;
+  array<NestedStruct> f_struct_array;
+  array<TestUnion> f_union_array;
+  map<string, int32> f_map;
+};