Add CdmFileIOProvider interface for use by cdm_adapter

media/cdm/cdm_file_io_provider.h

+// 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.
+
+#ifndef MEDIA_CDM_CDM_FILE_IO_PROVIDER_H_
+#define MEDIA_CDM_CDM_FILE_IO_PROVIDER_H_
+
+#include "base/macros.h"
+#include "media/base/media_export.h"
+
+namespace cdm {
+class FileIO;
+class FileIOClient;
+}
+
+namespace media {
+
+class MEDIA_EXPORT CdmFileIOProvider {
+ public:
+  CdmFileIOProvider();
+  virtual ~CdmFileIOProvider();
+
+  // Creates a FileIO object from the host to do file IO operation. Returns
+  // NULL if a FileIO object cannot be obtained. Once a valid FileIO object
+  // is returned, |client| must be valid until FileIO::Close() is called. The
+  // CDM can call this method multiple times to operate on different files.
+  virtual cdm::FileIO* CreateFileIO(cdm::FileIOClient* client) = 0;

[xhwang, 2016/04/14 06:46:31]

Since this interface only has one Create* method, will it work (and be simpler)
if we just pass a callback into CdmAdapter?

e.g.

Callback<unique_ptr<cdm::FileIO>(client)>

[jrummell, 2016/04/14 22:02:56]

Done.

+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CdmFileIOProvider);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_CDM_CDM_FILE_IO_PROVIDER_H_