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

webrtc/modules/video_coding/codecs/vp8/vp8_impl.h

Index: webrtc/modules/video_coding/codecs/vp8/vp8_impl.h
diff --git a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.h b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.h
index 00a711554d5a5e367f7ebeccf8065d81731c2658..1937941e35773871c8c8e9f10db868062423fc33 100644
--- a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.h
+++ b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.h
@@ -56,6 +56,8 @@ class VP8EncoderImpl : public VP8Encoder {
   int SetChannelParameters(uint32_t packet_loss, int64_t rtt) override;
 
   int SetRates(uint32_t new_bitrate_kbit, uint32_t frame_rate) override;
+  int SetRateAllocation(const BitrateAllocation& bitrate,
+                        uint32_t new_framerate) override;
 
   void OnDroppedFrame() override;
 
@@ -64,7 +66,8 @@ class VP8EncoderImpl : public VP8Encoder {
  private:
   void SetupTemporalLayers(int num_streams,
                            int num_temporal_layers,
-                           const VideoCodec& codec);
+                           const VideoCodec& codec,
+                           SimulcastRateAllocator* allocator);
 
   // Set the cpu_speed setting for encoder based on resolution and/or platform.
   int SetCpuSpeed(int width, int height);
@@ -94,7 +97,8 @@ class VP8EncoderImpl : public VP8Encoder {
 
   EncodedImageCallback* encoded_complete_callback_;
   VideoCodec codec_;
-  std::unique_ptr<SimulcastRateAllocator> rate_allocator_;
+  std::unique_ptr<SimulcastRateAllocator> fallback_rate_allocator_;
+  std::unique_ptr<TemporalLayersFactory> fallback_tl_factory_;
   bool inited_;
   int64_t timestamp_;
   bool feedback_mode_;