Add allocator interface for use by cdm_adapter

media/cdm/cdm_buffer_allocator.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_BUFFER_ALLOCATOR_H_
+#define MEDIA_CDM_CDM_BUFFER_ALLOCATOR_H_
+
+#include <stdint.h>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class CdmBuffer;
+class CdmVideoFrame;
+
+class MEDIA_EXPORT CdmBufferAllocator {
+ public:
+  virtual ~CdmBufferAllocator();
+
+  // Allocates a buffer with at least |capacity| bytes. The caller owns the
+  // buffer, and must call Release() when it is done with the memory.

[xhwang, 2016/02/11 19:24:13]

The Allocate and Release calls exist on PpbBufferAllocator toady. But
PpbBufferAllocator runs in the plugin and we have very little room for smarter
programming :(

Now since we are using scoped_refptr, having to call Release() sounds a weird
requirement. Usually if we want something like this, Release() will be
automatically called in the destructor of CdmBuffer.

[jrummell, 2016/02/11 22:08:16]

Changed to simply return cdm::Buffer. No more refptr.

+  virtual scoped_refptr<CdmBuffer> Allocate(uint32_t capacity) = 0;
+
+  // Releases the buffer. A buffer can be recycled after it is released.
+  virtual void Release(scoped_refptr<CdmBuffer> buffer) = 0;
+
+  // Returns a new VideoFrameImpl.
+  virtual scoped_ptr<CdmVideoFrame> CreateCdmVideoFrame() = 0;

[xhwang, 2016/02/11 19:24:13]

This class can create a VideoFrame now. Maybe we should rename this class to
just CdmAllocator.

[jrummell, 2016/02/11 22:08:15]

Done.

+
+ protected:
+  CdmBufferAllocator();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CdmBufferAllocator);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_CDM_CDM_BUFFER_ALLOCATOR_H_