Add the frame provider base class used in cast media.

chromecast/media/cma/base/coded_frame_provider.h

+// 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.
+
+#ifndef CHROMECAST_MEDIA_CMA_BASE_CODED_FRAME_PROVIDER_H_
+#define CHROMECAST_MEDIA_CMA_BASE_CODED_FRAME_PROVIDER_H_
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+
+namespace media {
+class AudioDecoderConfig;
+class VideoDecoderConfig;
+}
+
+namespace chromecast {
+namespace media {
+class DecoderBufferBase;
+
+class CodedFrameProvider {
+ public:
+  typedef base::Callback<void(const scoped_refptr<DecoderBufferBase>&,
+                              const ::media::AudioDecoderConfig&,
+                              const ::media::VideoDecoderConfig&)> ReadCB;
+
+  CodedFrameProvider();
+  virtual ~CodedFrameProvider();
+
+  // Request a coded frame which is provided asynchronously through callback
+  // |read_cb|.
+  // If the frame is associated with a new video/audio configuration,
+  // these configurations are returned as part of the |read_cb| callback.
+  // Invoking the |read_cb| callback with invalid audio/video configurations
+  // means the configurations have not changed.
+  virtual void Read(const ReadCB& read_cb) = 0;
+
+  // Flush the coded frames held by the frame provider.
+  // Invoke callback |flush_cb| when completed.
+  // Note: any pending read is cancelled, meaning that any pending |read_cb|
+  // callback will not be invoked.
+  virtual void Flush(const base::Closure& flush_cb) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CodedFrameProvider);
+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_CMA_BASE_CODED_FRAME_PROVIDER_H_