Use Android callback API to obtain cellular signal strength

net/nqe/network_quality_estimator_params.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_NQE_NETWORK_QUALITY_ESTIMATOR_PARAMS_H_
 #define NET_NQE_NETWORK_QUALITY_ESTIMATOR_PARAMS_H_
 
 #include <map>
 #include <string>
 
@@ skipping 56 matching lines @@
     return throughput_min_requests_in_flight_;
   }
 
   // Returns the weight multiplier per second, which represents the factor by
   // which the weight of an observation reduces every second.
   double weight_multiplier_per_second() const {
     return weight_multiplier_per_second_;
   }
 
   // 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 weight_multiplier_per_dbm() const {
-    return weight_multiplier_per_dbm_;
+  // signal strength level difference between the current signal strength, and
+  // the signal strength at the time when the observation was taken.
+  double weight_multiplier_per_signal_strength_level() const {
+    return weight_multiplier_per_signal_strength_level_;
   }
 
   // Returns the fraction of URL requests that should record the correlation
   // UMA.
   double correlation_uma_logging_probability() const {
     return correlation_uma_logging_probability_;
   }
 
   // Returns an unset value if the effective connection type has not been forced
   // via the |params| provided to this class. Otherwise, returns a value set to
@@ skipping 14 matching lines @@
     return min_socket_watcher_notification_interval_;
   }
 
  private:
   // Map containing all field trial parameters related to
   // NetworkQualityEstimator field trial.
   const std::map<std::string, std::string> params_;
 
   const size_t throughput_min_requests_in_flight_;
   const double weight_multiplier_per_second_;
-  const double weight_multiplier_per_dbm_;
+  const double weight_multiplier_per_signal_strength_level_;
   const double correlation_uma_logging_probability_;
   const base::Optional<EffectiveConnectionType>
       forced_effective_connection_type_;
   const bool persistent_cache_reading_enabled_;
   const base::TimeDelta min_socket_watcher_notification_interval_;
 
   // Default network quality observations obtained from |params_|.
   NetworkQuality
       default_observations_[NetworkChangeNotifier::CONNECTION_LAST + 1];
 
@@ skipping 13 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimatorParams);
 };
 
 }  // namespace internal
 
 }  // namespace nqe
 
 }  // namespace net
 
 #endif  // NET_NQE_NETWORK_QUALITY_ESTIMATOR_PARAMS_H_