Use Android callback API to obtain cellular signal strength

net/nqe/network_quality_estimator_params.h

Index: net/nqe/network_quality_estimator_params.h
diff --git a/net/nqe/network_quality_estimator_params.h b/net/nqe/network_quality_estimator_params.h
index 6d7310f95ea78d8c5816dee522768492ed366dcd..06983ca88b8d8fa40ed92f0826585677cb412423 100644
--- a/net/nqe/network_quality_estimator_params.h
+++ b/net/nqe/network_quality_estimator_params.h
@@ -32,9 +32,9 @@ double GetWeightMultiplierPerSecond(
     const std::map<std::string, std::string>& variation_params);
 
 // Returns the factor by which the weight of an observation reduces for every
-// dBm difference between the current signal strength (in dBm), and the signal
-// strength at the time when the observation was taken.
-double GetWeightMultiplierPerDbm(
+// signal strength level difference between the current signal strength, and
+// the signal strength at the time when the observation was taken.
+double GetWeightMultiplierPerSignalStrengthLevel(
     const std::map<std::string, std::string>& variation_params);
 
 // Returns a descriptive name corresponding to |connection_type|.