Support read-only duplicates of Mojo shared buffers.

mojo/edk/test/mojo_test_base.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/edk/test/mojo_test_base.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "mojo/edk/embedder/embedder.h"
 #include "mojo/edk/system/handle_signals_state.h"
@@ skipping 206 matching lines @@
 }
 
 // static
 MojoHandle MojoTestBase::CreateBuffer(uint64_t size) {
   MojoHandle h;
   EXPECT_EQ(MojoCreateSharedBuffer(nullptr, size, &h), MOJO_RESULT_OK);
   return h;
 }
 
 // static
-MojoHandle MojoTestBase::DuplicateBuffer(MojoHandle h) {
+MojoHandle MojoTestBase::DuplicateBuffer(MojoHandle h, bool read_only) {
   MojoHandle new_handle;
+  MojoDuplicateBufferHandleOptions options = {
+    sizeof(MojoDuplicateBufferHandleOptions),
+    MOJO_DUPLICATE_BUFFER_HANDLE_OPTIONS_FLAG_NONE
+  };
+  if (read_only)
+    options.flags |= MOJO_DUPLICATE_BUFFER_HANDLE_OPTIONS_FLAG_READ_ONLY;
   EXPECT_EQ(MOJO_RESULT_OK,
-            MojoDuplicateBufferHandle(h, nullptr, &new_handle));
+            MojoDuplicateBufferHandle(h, &options, &new_handle));
   return new_handle;
 }
 
 // static
 void MojoTestBase::WriteToBuffer(MojoHandle h,
                                  size_t offset,
                                  const base::StringPiece& s) {
   char* data;
   EXPECT_EQ(MOJO_RESULT_OK,
             MojoMapBuffer(h, offset, s.size(), reinterpret_cast<void**>(&data),
@@ skipping 52 matching lines @@
                          MOJO_WRITE_DATA_FLAG_ALL_OR_NONE),
            MOJO_RESULT_OK);
   CHECK_EQ(num_bytes, static_cast<uint32_t>(size));
 
   return std::string(buffer.data(), buffer.size());
 }
 
 }  // namespace test
 }  // namespace edk
 }  // namespace mojo