Extract bitrate allocation of spatial/temporal layers out of codec impl.

webrtc/common_video/include/video_bitrate_allocator.h

+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_COMMON_VIDEO_INCLUDE_VIDEO_BITRATE_ALLOCATOR_H_
+#define WEBRTC_COMMON_VIDEO_INCLUDE_VIDEO_BITRATE_ALLOCATOR_H_
+
+#include "webrtc/common_types.h"
+
+namespace webrtc {
+
+class VideoBitrateAllocator {
+ public:
+  VideoBitrateAllocator() {}
+  virtual ~VideoBitrateAllocator() {}

[perkj_webrtc, 2016/10/21 08:24:28]

make destructor protected unless it should be possible to delete the
implementation through this interface.

[sprang_webrtc, 2016/10/25 10:44:25]

ViEEncoder has a std::unique_ptr<VideoBitrateAllocator>, so yes - the destructor
needs to be public.

+
+  virtual BitrateAllocation GetAllocation(uint32_t total_bitrate,
+                                          uint32_t framerate) = 0;
+  virtual uint32_t GetPreferedBitrate(int frame_rate) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_COMMON_VIDEO_INCLUDE_VIDEO_BITRATE_ALLOCATOR_H_