Allow Mojo structs as map keys

mojo/public/cpp/bindings/tests/hash_unittest.cc

+// 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.
+
+#include "mojo/public/cpp/bindings/lib/hash_util.h"
+
+#include "mojo/public/interfaces/bindings/tests/test_structs.mojom.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace test {
+namespace {
+
+using HashTest = testing::Test;
+
+static ContainsOtherPtr MakeContainsOther(uint64_t other) {
+  ContainsOtherPtr ptr = ContainsOther::New();
+  ptr->other = other;
+  return ptr;
+}
+
+static SimpleNestedStructPtr MakeSimpleNestedStruct(ContainsOtherPtr nested) {
+  SimpleNestedStructPtr ptr = SimpleNestedStruct::New();
+  ptr->nested = std::move(nested);
+  return ptr;
+}
+
+TEST_F(HashTest, NestedStruct) {
+  ASSERT_EQ(2007u, ::mojo::internal::Hash(
+                       ::mojo::internal::kHashSeed,
+                       MakeSimpleNestedStruct(MakeContainsOther(1))));
+}
+
+TEST_F(HashTest, UnmappedNativeStruct) {
+  ASSERT_EQ(31u, ::mojo::internal::Hash(::mojo::internal::kHashSeed,
+                                        UnmappedNativeStruct::New()));
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace mojo