Adds USB writing for OS X.

chrome/utility/image_writer/image_writer_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 <string>
 
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/run_loop.h"
 #include "chrome/utility/image_writer/error_messages.h"
@@ skipping 209 matching lines @@
   EXPECT_CALL(mock_handler, SendSucceeded()).Times(2);
   EXPECT_CALL(mock_handler, SendFailed(_)).Times(0);
 
   FillDefault(image_path_);
 
   image_writer.Write();
 
   base::RunLoop().RunUntilIdle();
 }
 
+TEST_F(ImageWriterUtilityTest, UnmountMac) {
+  base::RunLoop loop;
+  const base::Closure quit_closure = loop.QuitClosure();
+
+  VerifyingHandler mock_handler;
+  ImageWriter image_writer(&mock_handler, image_path_, base::FilePath("disk3"));
+
+  mock_handler.image_writer_ = &image_writer;
+
+  image_writer.UnmountVolumes(quit_closure);
+
+  loop.Run();
+}
+
 }  // namespace image_writer