For c++, Generate enum classes instead of enum from mojom.

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

 // 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.
 
 #include <vector>
 #include "mojo/public/cpp/bindings/array.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/bindings/lib/array_internal.h"
 #include "mojo/public/cpp/bindings/lib/array_serialization.h"
 #include "mojo/public/cpp/bindings/lib/bounds_checker.h"
@@ skipping 65 matching lines @@
   EXPECT_TRUE(pod->is_f_double());
   EXPECT_EQ(pod->which(), PodUnion::Tag::F_DOUBLE);
 
   pod->set_f_bool(true);
   EXPECT_TRUE(pod->get_f_bool());
   pod->set_f_bool(false);
   EXPECT_FALSE(pod->get_f_bool());
   EXPECT_TRUE(pod->is_f_bool());
   EXPECT_EQ(pod->which(), PodUnion::Tag::F_BOOL);
 
-  pod->set_f_enum(AN_ENUM_SECOND);
-  EXPECT_EQ(AN_ENUM_SECOND, pod->get_f_enum());
+  pod->set_f_enum(AnEnum::SECOND);
+  EXPECT_EQ(AnEnum::SECOND, pod->get_f_enum());
   EXPECT_TRUE(pod->is_f_enum());
   EXPECT_EQ(pod->which(), PodUnion::Tag::F_ENUM);
 }
 
 TEST(UnionTest, PodEquals) {
   PodUnionPtr pod1(PodUnion::New());
   PodUnionPtr pod2(PodUnion::New());
 
   pod1->set_f_int8(10);
   pod2->set_f_int8(10);
@@ skipping 30 matching lines @@
   PodUnionPtr pod2(PodUnion::New());
   Deserialize_(data, pod2.get());
 
   EXPECT_EQ(10, pod2->get_f_int8());
   EXPECT_TRUE(pod2->is_f_int8());
   EXPECT_EQ(pod2->which(), PodUnion::Tag::F_INT8);
 }
 
 TEST(UnionTest, EnumSerialization) {
   PodUnionPtr pod1(PodUnion::New());
-  pod1->set_f_enum(AN_ENUM_SECOND);
+  pod1->set_f_enum(AnEnum::SECOND);
 
   size_t size = GetSerializedSize_(pod1, false);
   EXPECT_EQ(16U, size);
 
   mojo::internal::FixedBufferForTesting buf(size);
   internal::PodUnion_Data* data = nullptr;
   SerializeUnion_(pod1.get(), &buf, &data, false);
 
   PodUnionPtr pod2 = PodUnion::New();
   Deserialize_(data, pod2.get());
 
-  EXPECT_EQ(AN_ENUM_SECOND, pod2->get_f_enum());
+  EXPECT_EQ(AnEnum::SECOND, pod2->get_f_enum());
   EXPECT_TRUE(pod2->is_f_enum());
   EXPECT_EQ(pod2->which(), PodUnion::Tag::F_ENUM);
 }
 
 TEST(UnionTest, PodValidation) {
   PodUnionPtr pod(PodUnion::New());
   pod->set_f_int8(10);
 
   size_t size = GetSerializedSize_(pod, false);
   EXPECT_EQ(16U, size);
@@ skipping 1008 matching lines @@
   PodUnionPtr pod(PodUnion::New());
   pod->set_f_int16(16);
 
   ptr->Echo(pod.Pass(),
             [](PodUnionPtr out) { EXPECT_EQ(16, out->get_f_int16()); });
   run_loop.RunUntilIdle();
 }
 
 }  // namespace test
 }  // namespace mojo