NQE: Make params a class

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>
 
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
 #include "net/base/network_change_notifier.h"
 #include "net/nqe/effective_connection_type.h"
 #include "net/nqe/network_quality.h"
 
 namespace net {
 
 namespace nqe {
 
 namespace internal {
 
-// Returns the algorithm that should be used for computing effective connection
-// type based on field trial params. Returns an empty string if a valid
-// algorithm paramter is not present in the field trial params.
-std::string GetEffectiveConnectionTypeAlgorithm(
-    const std::map<std::string, std::string>& variation_params);
+// NetworkQualityEstimatorParams computes the configuration parameters for
+// the network quality estimator.
+class NetworkQualityEstimatorParams {
+ public:
+  // |params| is the map containing all field trial parameters related to
+  // NetworkQualityEstimator field trial.
+  explicit NetworkQualityEstimatorParams(
+      const std::map<std::string, std::string>& params);
 
-// Computes and returns the weight multiplier per second, which represents the
-// factor by which the weight of an observation reduces every second.
-// |variation_params| is the map containing all field trial parameters
-// related to the NetworkQualityualityEstimator field trial.
-double GetWeightMultiplierPerSecond(
-    const std::map<std::string, std::string>& variation_params);
+  ~NetworkQualityEstimatorParams();
 
-// 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(
-    const std::map<std::string, std::string>& variation_params);
+  // Returns the algorithm that should be used for computing effective
+  // connection type. Returns an empty string if a valid algorithm paramter is
+  // not specified.
+  std::string GetEffectiveConnectionTypeAlgorithm() const;
 
-// Returns a descriptive name corresponding to |connection_type|.
-const char* GetNameForConnectionType(
-    net::NetworkChangeNotifier::ConnectionType connection_type);
+  // Computes and returns the weight multiplier per second, which represents the
+  // factor by which the weight of an observation reduces every second.
+  double GetWeightMultiplierPerSecond() const;
 
-// Sets the default observation for different connection types in
-// |default_observations|. The default observations are different for different
-// connection types (e.g., 2G, 3G, 4G, WiFi). The default observations may be
-// used to determine the network quality in absence of any other information.
-void ObtainDefaultObservations(
-    const std::map<std::string, std::string>& variation_params,
-    nqe::internal::NetworkQuality default_observations[]);
+  // 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() const;
 
-// Sets |typical_network_quality| to typical network quality for different
-// effective connection types.
-void ObtainTypicalNetworkQuality(NetworkQuality typical_network_quality[]);
+  // Returns a descriptive name corresponding to |connection_type|.
+  static const char* GetNameForConnectionType(
+      net::NetworkChangeNotifier::ConnectionType connection_type);
 
-// Parses the variation paramaters and sets the thresholds for different
-// effective connection types in |connection_thresholds|.
-void ObtainEffectiveConnectionTypeModelParams(
-    const std::map<std::string, std::string>& variation_params,
-    nqe::internal::NetworkQuality connection_thresholds[]);
+  // Sets the default observation for different connection types in
+  // |default_observations|. The default observations are different for
+  // different connection types (e.g., 2G, 3G, 4G, WiFi). The default
+  // observations may be used to determine the network quality in absence of any
+  // other information.
+  void ObtainDefaultObservations(
+      nqe::internal::NetworkQuality default_observations[]) const;
 
-// Returns the fraction of URL requests that should record the correlation UMA.
-double correlation_uma_logging_probability(
-    const std::map<std::string, std::string>& variation_params);
+  // Sets |typical_network_quality| to typical network quality for different
+  // effective connection types.
+  void ObtainTypicalNetworkQuality(
+      NetworkQuality typical_network_quality[]) const;
 
-// Returns true if the effective connection type has been determined via
-// variation parameters.
-bool forced_effective_connection_type_set(
-    const std::map<std::string, std::string>& variation_params);
+  // Sets the thresholds for different effective connection types in
+  // |connection_thresholds|.
+  void ObtainEffectiveConnectionTypeModelParams(
+      nqe::internal::NetworkQuality connection_thresholds[]) const;
 
-// Returns the effective connection type that was configured by variation
-// parameters.
-EffectiveConnectionType forced_effective_connection_type(
-    const std::map<std::string, std::string>& variation_params);
+  // Returns the fraction of URL requests that should record the correlation
+  // UMA.
+  double correlation_uma_logging_probability() const;
 
-// Returns true if reading from the persistent cache has been enabled via field
-// trial.
-bool persistent_cache_reading_enabled(
-    const std::map<std::string, std::string>& variation_params);
+  // Returns true if the effective connection type has been forced via field
+  // trial parameters.
+  bool forced_effective_connection_type_set() const;
 
-// Returns the the minimum interval betweeen consecutive notifications to a
-// single socket watcher.
-base::TimeDelta GetMinSocketWatcherNotificationInterval(
-    const std::map<std::string, std::string>& variation_params);
+  // Returns the effective connection type if it has been forced via field trial
+  // parameters.
+  EffectiveConnectionType forced_effective_connection_type() const;
+
+  // Returns true if reading from the persistent cache is enabled.
+  bool persistent_cache_reading_enabled() const;
+
+  // Returns the the minimum interval betweeen consecutive notifications to a
+  // single socket watcher.
+  base::TimeDelta GetMinSocketWatcherNotificationInterval() const;
+
+ private:
+  // Map containing all field trial parameters related to
+  // NetworkQualityEstimator field trial.
+  const std::map<std::string, std::string> params_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimatorParams);
+};
 
 }  // namespace internal
 
 }  // namespace nqe
 
 }  // namespace net
 
 #endif  // NET_NQE_NETWORK_QUALITY_ESTIMATOR_PARAMS_H_