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

webrtc/test/fake_encoder.h

Index: webrtc/test/fake_encoder.h
diff --git a/webrtc/test/fake_encoder.h b/webrtc/test/fake_encoder.h
index ae869fff6abe0fd93547e51771d9f1d0f4913214..3fd914cb658073aac8f8ef66ba221a152a1e258f 100644
--- a/webrtc/test/fake_encoder.h
+++ b/webrtc/test/fake_encoder.h
@@ -38,7 +38,8 @@ class FakeEncoder : public VideoEncoder {
       EncodedImageCallback* callback) override;
   int32_t Release() override;
   int32_t SetChannelParameters(uint32_t packet_loss, int64_t rtt) override;
-  int32_t SetRates(uint32_t new_target_bitrate, uint32_t framerate) override;
+  int32_t SetRateAllocation(const BitrateAllocation& rate_allocation,
+                            uint32_t framerate) override;
   const char* ImplementationName() const override;
 
   static const char* kImplementationName;
@@ -47,7 +48,7 @@ class FakeEncoder : public VideoEncoder {
   Clock* const clock_;
   VideoCodec config_;
   EncodedImageCallback* callback_;
-  int target_bitrate_kbps_;
+  BitrateAllocation target_bitrate_;
   int max_target_bitrate_kbps_;
   int64_t last_encode_time_ms_;
   uint8_t encoded_buffer_[100000];