EDK: Add Core::DuplicateHandleWithReducedRights().

mojo/edk/system/shared_buffer_dispatcher_unittest.cc

Index: mojo/edk/system/shared_buffer_dispatcher_unittest.cc
diff --git a/mojo/edk/system/shared_buffer_dispatcher_unittest.cc b/mojo/edk/system/shared_buffer_dispatcher_unittest.cc
index fa90b239796fce39d26a78927b76c4b115ba6324..bf8a1ddbf46073e290a9b91dcca98b7bb328bf6d 100644
--- a/mojo/edk/system/shared_buffer_dispatcher_unittest.cc
+++ b/mojo/edk/system/shared_buffer_dispatcher_unittest.cc
@@ -203,6 +203,49 @@ TEST_F(SharedBufferDispatcherTest, SupportsEntrypointClass) {
   EXPECT_EQ(MOJO_RESULT_OK, d->Close());
 }
 
+TEST_F(SharedBufferDispatcherTest, DuplicateDispatcher) {
+  const uint64_t kSize = 100u;
+
+  MojoResult result = MOJO_RESULT_INTERNAL;
+  auto dispatcher1 = SharedBufferDispatcher::Create(
+      platform_support(), SharedBufferDispatcher::kDefaultCreateOptions, kSize,
+      &result);
+  EXPECT_EQ(MOJO_RESULT_OK, result);
+
+  // Map and write something.
+  std::unique_ptr<PlatformSharedBufferMapping> mapping;
+  EXPECT_EQ(
+      MOJO_RESULT_OK,
+      dispatcher1->MapBuffer(0u, kSize, MOJO_MAP_BUFFER_FLAG_NONE, &mapping));
+  static_cast<char*>(mapping->GetBase())[0] = 'x';
+  mapping.reset();
+
+  // Duplicate |dispatcher1| and then close it.
+  RefPtr<Dispatcher> dispatcher2;
+  EXPECT_EQ(MOJO_RESULT_OK, dispatcher1->DuplicateDispatcher(&dispatcher2));
+  ASSERT_TRUE(dispatcher2);
+  EXPECT_EQ(Dispatcher::Type::SHARED_BUFFER, dispatcher2->GetType());
+
+  EXPECT_EQ(MOJO_RESULT_OK, dispatcher1->Close());
+
+  // Make sure that |dispatcher2| still reports the right information.
+  MojoBufferInformation info = {};
+  EXPECT_EQ(MOJO_RESULT_OK,
+            dispatcher2->GetBufferInformation(
+                MakeUserPointer(&info), static_cast<uint32_t>(sizeof(info))));
+  EXPECT_EQ(sizeof(MojoBufferInformation), info.struct_size);
+  EXPECT_EQ(MOJO_BUFFER_INFORMATION_FLAG_NONE, info.flags);
+  EXPECT_EQ(kSize, info.num_bytes);
+
+  // Map |dispatcher2| and read something.
+  EXPECT_EQ(
+      MOJO_RESULT_OK,
+      dispatcher2->MapBuffer(0u, kSize, MOJO_MAP_BUFFER_FLAG_NONE, &mapping));
+  EXPECT_EQ('x', static_cast<char*>(mapping->GetBase())[0]);
+
+  EXPECT_EQ(MOJO_RESULT_OK, dispatcher2->Close());
+}
+
 TEST_F(SharedBufferDispatcherTest, DuplicateBufferHandle) {
   const uint64_t kSize = 100u;