Move Pipeline permanent callbacks into Pipeline::Client interface.

media/base/pipeline_metadata.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_BASE_PIPELINE_METADATA_H_
+#define MEDIA_BASE_PIPELINE_METADATA_H_
+
+#include "base/time/time.h"
+#include "media/base/video_rotation.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace media {
+
+// Metadata describing a pipeline once it has been initialized.
+struct PipelineMetadata {
+  PipelineMetadata()
+      : has_audio(false), has_video(false), video_rotation(VIDEO_ROTATION_0) {}
+
+  bool has_audio;
+  bool has_video;
+  gfx::Size natural_size;
+  VideoRotation video_rotation;
+  base::Time timeline_offset;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_PIPELINE_METADATA_H_