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..c4239e3a93f142b8ff08fd5b0e691dce87ae7333 100644
--- a/webrtc/modules/video_coding/codecs/vp8/vp8_impl.h
+++ b/webrtc/modules/video_coding/codecs/vp8/vp8_impl.h
@@ -32,7 +32,6 @@
 
 namespace webrtc {
 
-class SimulcastRateAllocator;
 class TemporalLayers;
 
 class VP8EncoderImpl : public VP8Encoder {
@@ -55,7 +54,8 @@ 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;
 
@@ -94,7 +94,6 @@ class VP8EncoderImpl : public VP8Encoder {
 
   EncodedImageCallback* encoded_complete_callback_;
   VideoCodec codec_;
-  std::unique_ptr<SimulcastRateAllocator> rate_allocator_;
   bool inited_;
   int64_t timestamp_;
   bool feedback_mode_;