Support read-only duplicates of Mojo shared buffers.

mojo/edk/system/shared_buffer_dispatcher_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 "mojo/edk/system/shared_buffer_dispatcher.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <limits>
@@ skipping 202 matching lines @@
 
 TEST_F(SharedBufferDispatcherTest, DuplicateBufferHandleOptionsValid) {
   scoped_refptr<SharedBufferDispatcher> dispatcher1;
   EXPECT_EQ(MOJO_RESULT_OK, SharedBufferDispatcher::Create(
                                 SharedBufferDispatcher::kDefaultCreateOptions,
                                 nullptr, 100, &dispatcher1));
 
   MojoDuplicateBufferHandleOptions options[] = {
       {sizeof(MojoDuplicateBufferHandleOptions),
        MOJO_DUPLICATE_BUFFER_HANDLE_OPTIONS_FLAG_NONE},
+      {sizeof(MojoDuplicateBufferHandleOptions),
+       MOJO_DUPLICATE_BUFFER_HANDLE_OPTIONS_FLAG_READ_ONLY},
       {sizeof(MojoDuplicateBufferHandleOptionsFlags), ~0u}};
   for (size_t i = 0; i < arraysize(options); i++) {
     scoped_refptr<Dispatcher> dispatcher2;
     EXPECT_EQ(MOJO_RESULT_OK, dispatcher1->DuplicateBufferHandle(
                                   &options[i], &dispatcher2));
     ASSERT_TRUE(dispatcher2);
     EXPECT_EQ(Dispatcher::Type::SHARED_BUFFER, dispatcher2->GetType());
+    {
+      scoped_ptr<PlatformSharedBufferMapping> mapping;
+      EXPECT_EQ(MOJO_RESULT_OK, dispatcher2->MapBuffer(0, 100, 0, &mapping));
+    }
     EXPECT_EQ(MOJO_RESULT_OK, dispatcher2->Close());
   }
 
   EXPECT_EQ(MOJO_RESULT_OK, dispatcher1->Close());
 }
 
 TEST_F(SharedBufferDispatcherTest, DuplicateBufferHandleOptionsInvalid) {
   scoped_refptr<SharedBufferDispatcher> dispatcher1;
   EXPECT_EQ(MOJO_RESULT_OK, SharedBufferDispatcher::Create(
                                 SharedBufferDispatcher::kDefaultCreateOptions,
@@ skipping 57 matching lines @@
   EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT,
             dispatcher->MapBuffer(0, 0, MOJO_MAP_BUFFER_FLAG_NONE, &mapping));
   EXPECT_FALSE(mapping);
 
   EXPECT_EQ(MOJO_RESULT_OK, dispatcher->Close());
 }
 
 }  // namespace
 }  // namespace edk
 }  // namespace mojo