Treat WiFi connection same as 4G

Treat WiFi connection same as 4G when computing the ECT.

Change-Id: I5d1ed46227b1d19b50a30996b2e3e8a551b82b9d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1706871Reviewed-by: Ryan Sturm <ryansturm@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#678557}

net/nqe/network_quality_estimator.cc

@@ -929,32 +929,32 @@ NetworkQualityEstimator::GetCappedECTBasedOnSignalStrength() const {
   if (current_network_id_.signal_strength == INT32_MIN)
     return effective_connection_type_;
 
-  // Capping ECT on WiFi is currently not enabled.
+  if (effective_connection_type_ == EFFECTIVE_CONNECTION_TYPE_UNKNOWN ||
+      effective_connection_type_ == EFFECTIVE_CONNECTION_TYPE_OFFLINE) {
+    return effective_connection_type_;
+  }
+
   if (current_network_id_.type == NetworkChangeNotifier::CONNECTION_WIFI) {
     // The maximum signal strength level is 4.
     UMA_HISTOGRAM_EXACT_LINEAR("NQE.WifiSignalStrength.AtECTComputation",
                                current_network_id_.signal_strength, 4);
+  } else if (current_network_id_.type == NetworkChangeNotifier::CONNECTION_2G ||
+             current_network_id_.type == NetworkChangeNotifier::CONNECTION_3G ||
+             current_network_id_.type == NetworkChangeNotifier::CONNECTION_4G) {
+    // The maximum signal strength level is 4.
+    UMA_HISTOGRAM_EXACT_LINEAR("NQE.CellularSignalStrength.AtECTComputation",
+                               current_network_id_.signal_strength, 4);
+  } else {
+    NOTREACHED();
     return effective_connection_type_;
   }
 
-  if (effective_connection_type_ == EFFECTIVE_CONNECTION_TYPE_UNKNOWN ||
-      effective_connection_type_ == EFFECTIVE_CONNECTION_TYPE_OFFLINE) {
-    return effective_connection_type_;
-  }
-
-  // The maximum signal strength level is 4.
-  UMA_HISTOGRAM_EXACT_LINEAR("NQE.CellularSignalStrength.AtECTComputation",
-                             current_network_id_.signal_strength, 4);
-
   // Do not cap ECT if the signal strength is high.
   if (current_network_id_.signal_strength > 2)
     return effective_connection_type_;
 
   DCHECK_LE(0, current_network_id_.signal_strength);
 
-  DCHECK_LE(NetworkChangeNotifier::CONNECTION_2G, current_network_id_.type);
-  DCHECK_GE(NetworkChangeNotifier::CONNECTION_4G, current_network_id_.type);
-
   // When signal strength is 0, the device is almost offline.
   if (current_network_id_.signal_strength == 0) {
     switch (current_network_id_.type) {
@@ -963,6 +963,7 @@ NetworkQualityEstimator::GetCappedECTBasedOnSignalStrength() const {
         return std::min(effective_connection_type_,
                         EFFECTIVE_CONNECTION_TYPE_SLOW_2G);
       case NetworkChangeNotifier::CONNECTION_4G:
+      case NetworkChangeNotifier::CONNECTION_WIFI:
         return std::min(effective_connection_type_,
                         EFFECTIVE_CONNECTION_TYPE_2G);
       default:
@@ -980,6 +981,7 @@ NetworkQualityEstimator::GetCappedECTBasedOnSignalStrength() const {
         return std::min(effective_connection_type_,
                         EFFECTIVE_CONNECTION_TYPE_2G);
       case NetworkChangeNotifier::CONNECTION_4G:
+      case NetworkChangeNotifier::CONNECTION_WIFI:
         return std::min(effective_connection_type_,
                         EFFECTIVE_CONNECTION_TYPE_3G);
       default:
@@ -997,6 +999,7 @@ NetworkQualityEstimator::GetCappedECTBasedOnSignalStrength() const {
         return std::min(effective_connection_type_,
                         EFFECTIVE_CONNECTION_TYPE_3G);
       case NetworkChangeNotifier::CONNECTION_4G:
+      case NetworkChangeNotifier::CONNECTION_WIFI:
         return std::min(effective_connection_type_,
                         EFFECTIVE_CONNECTION_TYPE_4G);
       default:

net/nqe/network_quality_estimator_unittest.cc

@@ -1197,22 +1197,33 @@ TEST_F(NetworkQualityEstimatorTest, DefaultHttpRTTBasedThresholds) {
 TEST_F(NetworkQualityEstimatorTest, SignalStrengthBasedCapping) {
   const struct {
     bool enable_signal_strength_capping_experiment;
+    NetworkChangeNotifier::ConnectionType device_connection_type;
     int32_t signal_strength_level;
     int32_t http_rtt_msec;
     EffectiveConnectionType expected_ect;
     bool expected_http_rtt_overridden;
   } tests[] = {
       // Signal strength is unavailable.
-      {true, INT32_MIN, 20, EFFECTIVE_CONNECTION_TYPE_4G, false},
+      {true, NetworkChangeNotifier::CONNECTION_4G, INT32_MIN, 20,
+       EFFECTIVE_CONNECTION_TYPE_4G, false},
 
-      // Signal strength is too low. Even though RTT is reported as low,
+      // 4G device connection type: Signal strength is too low. Even though RTT
+      // is reported as low,
       // ECT is expected to be capped to 2G.
-      {true, 0, 20, EFFECTIVE_CONNECTION_TYPE_2G, true},
+      {true, NetworkChangeNotifier::CONNECTION_4G, 0, 20,
+       EFFECTIVE_CONNECTION_TYPE_2G, true},
+
+      // WiFi device connection type: Signal strength is too low. Even though
+      // RTT is reported as low, ECT is expected to be capped to 2G.
+      {true, NetworkChangeNotifier::CONNECTION_WIFI, 0, 20,
+       EFFECTIVE_CONNECTION_TYPE_2G, true},
 
       // When the signal strength based capping experiment is not enabled,
       // ECT should be computed only on the based of |http_rtt_msec|.
-      {false, INT32_MIN, 20, EFFECTIVE_CONNECTION_TYPE_4G, false},
-      {false, 0, 20, EFFECTIVE_CONNECTION_TYPE_4G, false},
+      {false, NetworkChangeNotifier::CONNECTION_4G, INT32_MIN, 20,
+       EFFECTIVE_CONNECTION_TYPE_4G, false},
+      {false, NetworkChangeNotifier::CONNECTION_4G, 0, 20,
+       EFFECTIVE_CONNECTION_TYPE_4G, false},
   };
 
   for (const auto& test : tests) {
@@ -1227,8 +1238,7 @@ TEST_F(NetworkQualityEstimatorTest, SignalStrengthBasedCapping) {
     // does not return Offline if the device is offline.
     estimator.SetCurrentSignalStrength(test.signal_strength_level);
 
-    estimator.SimulateNetworkChange(NetworkChangeNotifier::CONNECTION_4G,
-                                    "test");
+    estimator.SimulateNetworkChange(test.device_connection_type, "test");
 
     estimator.SetStartTimeNullHttpRtt(
         base::TimeDelta::FromMilliseconds(test.http_rtt_msec));