Add EffectiveConnectionType enum to the system profile proto

components/metrics/proto/system_profile.proto

Index: components/metrics/proto/system_profile.proto
diff --git a/components/metrics/proto/system_profile.proto b/components/metrics/proto/system_profile.proto
index c116a0a1d1909830675f3e6b3442cae3924b56d0..7020e763aeace6048aa4a7953b4a03d4b0c762c2 100644
--- a/components/metrics/proto/system_profile.proto
+++ b/components/metrics/proto/system_profile.proto
@@ -366,6 +366,22 @@ message SystemProfileProto {
     }
     // Information of the wireless AP that device is connected to.
     optional WifiAccessPoint access_point_info = 5;
+
+    // Derived from net::NetworkQualityEstimator::EffectiveConnectionType
+    // translated through NetworkMetricsProvider::GetConnectionType.
+    enum EffectiveConnectionType {
+      EFFECTIVE_CONNECTION_TYPE_UNKNOWN = 0;
+      EFFECTIVE_CONNECTION_TYPE_OFFLINE = 1;
+      EFFECTIVE_CONNECTION_TYPE_SLOW_2G = 2;
+      EFFECTIVE_CONNECTION_TYPE_2G = 3;
+      EFFECTIVE_CONNECTION_TYPE_3G = 4;
+      EFFECTIVE_CONNECTION_TYPE_4G = 5;
+      // Set to |EFFECTIVE_CONNECTION_TYPE_AMBIGUOUS| true if connection_type
+      // changed during the lifetime of the log.
+      EFFECTIVE_CONNECTION_TYPE_AMBIGUOUS = 6;
+    }
+    // The connection type according to net::NetworkQualityEstimator.
+    optional EffectiveConnectionType effective_connection_type = 6;
   }
   optional Network network = 13;