Expose cellular signal strength on Android to native

net/nqe/network_quality_estimator.h

Index: net/nqe/network_quality_estimator.h
diff --git a/net/nqe/network_quality_estimator.h b/net/nqe/network_quality_estimator.h
index c13ae601061a48b6c536a81b12f53ba7cc71ba39..20f233b450bbf720b701056485df1c382e63c68e 100644
--- a/net/nqe/network_quality_estimator.h
+++ b/net/nqe/network_quality_estimator.h
@@ -476,6 +476,11 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // main frame request is observed.
   void RecordAccuracyAfterMainFrame(base::TimeDelta measuring_duration) const;
 
+  // Obtains the current cellular signal strength value and updates
+  // |min_signal_strength_since_connection_change_| and
+  // |max_signal_strength_since_connection_change_|.
+  void UpdateSignalStrength();
+
   // Returns the effective type of the current connection based on only the
   // samples observed after |start_time|. Uses HTTP RTT and downstream
   // throughput to compute the effective connection type, and requires both of
@@ -604,6 +609,11 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // |effective_connection_type_recomputation_interval_| ago).
   EffectiveConnectionType effective_connection_type_;
 
+  // Minimum and Maximum signal strength (in dbM) observed since last connection
+  // change. Updated on connection change and main frame requests.
+  int32_t min_signal_strength_since_connection_change_;
+  int32_t max_signal_strength_since_connection_change_;
+
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<NetworkQualityEstimator> weak_ptr_factory_;