Added Network Quality Estimator Real-time interface to Cronet

net/base/network_quality_estimator.h

Index: net/base/network_quality_estimator.h
diff --git a/net/base/network_quality_estimator.h b/net/base/network_quality_estimator.h
index a32264f89703e90cfb600f25f82dad5ebbf8b6cc..e80ca62c526b71ac25f941d910e64568a260b668 100644
--- a/net/base/network_quality_estimator.h
+++ b/net/base/network_quality_estimator.h
@@ -13,7 +13,9 @@
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/observer_list_threadsafe.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "net/base/external_estimate_provider.h"
@@ -36,6 +38,55 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
     : public NetworkChangeNotifier::ConnectionTypeObserver,
       public ExternalEstimateProvider::UpdatedEstimateDelegate {
  public:
+  enum ObservationType { DOWNLINK_THROUGHPUT, RTT };
+
+  // On Android, a Java counterpart will be generated for this enum.
+  // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.net
+  // GENERATED_JAVA_CLASS_NAME_OVERRIDE: NetworkQualityObservationSource
+  // GENERATED_JAVA_PREFIX_TO_STRIP: OBSERVATION_SOURCE_
+  enum ObservationSource {
+    OBSERVATION_SOURCE_URL_REQUEST,
+    OBSERVATION_SOURCE_TCP,
+    OBSERVATION_SOURCE_QUIC,
+    OBSERVATION_SOURCE_CACHED_ESTIMATE,
+    OBSERVATION_SOURCE_DEFAULT_FROM_PLATFORM,
+    OBSERVATION_SOURCE_EXTERNAL_ESTIMATE
+  };
+
+  // Observes measurements of round trip time.
+  class NET_EXPORT_PRIVATE RTTObserver {
+   public:
+    // Will be called when a new RTT observation is available. The round trip
+    // times is specified in milliseconds.
+    virtual void OnRTTObservation(int32_t rtt_ms,
+                                  const base::TimeTicks& timestamp,
+                                  ObservationSource source) = 0;
+
+   protected:
+    RTTObserver() {}
+    virtual ~RTTObserver() {}
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(RTTObserver);
+  };
+
+  // Observes measurements of throughput.
+  class NET_EXPORT_PRIVATE ThroughputObserver {
+   public:
+    // Will be called when a new throughput observation is available.
+    // Throughput is specified in kilobits per second.
+    virtual void OnThroughputObservation(int32_t throughput_kbps,
+                                         const base::TimeTicks& timestamp,
+                                         ObservationSource source) = 0;
+
+   protected:
+    ThroughputObserver() {}
+    virtual ~ThroughputObserver() {}
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(ThroughputObserver);
+  };
+
   // Creates a new NetworkQualityEstimator.
   // |variation_params| is the map containing all field trial parameters
   // related to NetworkQualityEstimator field trial.
@@ -76,6 +127,13 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
       const base::TimeTicks& begin_timestamp,
       int32_t* kbps) const;
 
+  void AddRTTObserver(RTTObserver* rtt_observer);
+  void RemoveRTTObserver(RTTObserver* rtt_observer);
+  void AddThroughputObserver(ThroughputObserver* throughput_observer);
+  void RemoveThroughputObserver(ThroughputObserver* throughput_observer);
+
+  void Configure(bool allow_local_host_requests, bool allow_smaller_responses);
+
  protected:
   // NetworkID is used to uniquely identify a network.
   // For the purpose of network quality estimation and caching, a network is
@@ -213,9 +271,15 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   };
 
   // Records the round trip time or throughput observation, along with the time
-  // the observation was made.
+  // the observation was made. The units of value are type specific. For round
+  // trip time observations, the value is in milliseconds. For throughput,
+  // the value is in kilobits per second. Observations can be made at several
+  // places in the network stack, thus the observation source is provided as
+  // well.
   struct NET_EXPORT_PRIVATE Observation {
-    Observation(int32_t value, base::TimeTicks timestamp);
+    Observation(int32_t value,
+                base::TimeTicks timestamp,
+                ObservationSource source);
     ~Observation();
 
     // Value of the observation.
@@ -223,6 +287,9 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
 
     // Time when the observation was taken.
     const base::TimeTicks timestamp;
+
+    // The source of the observation.
+    ObservationSource source;
   };
 
   // Holds an observation and its weight.
@@ -378,6 +445,10 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // Writes the estimated quality of the current network to the cache.
   void CacheNetworkQualityEstimate();
 
+  void NotifyObserversOfRTT(const Observation& observation);
+
+  void NotifyObserversOfThroughput(const Observation& observation);
+
   // Records the UMA related to RTT.
   void RecordRTTUMA(int32_t estimated_value_msec,
                     int32_t actual_value_msec) const;
@@ -389,12 +460,12 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
 
   // Determines if the requests to local host can be used in estimating the
   // network quality. Set to true only for tests.
-  const bool allow_localhost_requests_;
+  bool allow_localhost_requests_;
 
   // Determines if the responses smaller than |kMinTransferSizeInBytes|
   // or shorter than |kMinTransferSizeInBytes| can be used in estimating the
   // network quality. Set to true only for tests.
-  const bool allow_small_responses_;
+  bool allow_small_responses_;
 
   // Time when last connection change was observed.
   base::TimeTicks last_connection_change_;
@@ -432,6 +503,11 @@ class NET_EXPORT_PRIVATE NetworkQualityEstimator
   // system APIs. May be NULL.
   const scoped_ptr<ExternalEstimateProvider> external_estimates_provider_;
 
+  // Observer lists for round trip times and throughput measurements.
+  scoped_refptr<base::ObserverListThreadSafe<RTTObserver>> rtt_observer_list_;
+  scoped_refptr<base::ObserverListThreadSafe<ThroughputObserver>>
+      throughput_observer_list_;
+
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimator);