[SM02] Support record mobile network stats by collapsed rat type

Previously network stats could be recorded by different rat type.
However, the feature was disabled by ag/173504 since rat type
frequently flapping between HSPA+ and UMTS.

Given that this feature might be useful for collecting metrics,
re-implement it based on current architecture and reduce the
overhead introduced by frequently flapping by:
  1. only react when rat type changes between 2G/3G/4G/5G.
  2. reduce the number of records by only recording a subset
     of rat type that represented for a given network class.
  3. enforce 1 second rate limit if flapping too much.

Note that the feature is still disabled but will be enabled
in follow-up patches.

Test: manual test
Bug: 129082217
Change-Id: Ic6b2f10f2c8b082820e0662eb9cee70d70d28cd6
Merged-In: Ic6b2f10f2c8b082820e0662eb9cee70d70d28cd6
(cherry picked from commit 15ab452e7e3f00289fbedbdb86c512ad560dda7e)

core/java/android/net/NetworkIdentity.java

@@ -25,6 +25,7 @@ import android.net.wifi.WifiInfo;
 import android.net.wifi.WifiManager;
 import android.os.Build;
 import android.service.NetworkIdentityProto;
+import android.telephony.Annotation.NetworkType;
 import android.util.Slog;
 import android.util.proto.ProtoOutputStream;
 
@@ -42,11 +43,8 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
     /**
      * When enabled, combine all {@link #mSubType} together under
      * {@link #SUBTYPE_COMBINED}.
-     *
-     * @deprecated we no longer offer to collect statistics on a per-subtype
-     *             basis; this is always disabled.
      */
-    @Deprecated
+    // TODO: make this flag configurable through settings. See http://b/146415925
     public static final boolean COMBINE_SUBTYPE_ENABLED = true;
 
     public static final int SUBTYPE_COMBINED = -1;
@@ -187,13 +185,14 @@ public class NetworkIdentity implements Comparable<NetworkIdentity> {
     }
 
     /**
-     * Build a {@link NetworkIdentity} from the given {@link NetworkState},
-     * assuming that any mobile networks are using the current IMSI.
+     * Build a {@link NetworkIdentity} from the given {@link NetworkState} and {@code subType},
+     * assuming that any mobile networks are using the current IMSI. The subType if applicable,
+     * should be set as one of the TelephonyManager.NETWORK_TYPE_* constants, or
+     * {@link android.telephony.TelephonyManager#NETWORK_TYPE_UNKNOWN} if not.
      */
     public static NetworkIdentity buildNetworkIdentity(Context context, NetworkState state,
-            boolean defaultNetwork) {
+            boolean defaultNetwork, @NetworkType int subType) {
         final int type = state.networkInfo.getType();
-        final int subType = state.networkInfo.getSubtype();
 
         String subscriberId = null;
         String networkId = null;

core/java/android/net/NetworkTemplate.java

@@ -37,6 +37,7 @@ import static android.net.wifi.WifiInfo.sanitizeSsid;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.telephony.TelephonyManager;
 import android.util.BackupUtils;
 import android.util.Log;
 
@@ -394,6 +395,45 @@ public class NetworkTemplate implements Parcelable {
         }
     }
 
+    /**
+     * Get a Radio Access Technology(RAT) type that is representative of a group of RAT types.
+     * The mapping is corresponding to {@code TelephonyManager#NETWORK_CLASS_BIT_MASK_*}.
+     *
+     * @param ratType An integer defined in {@code TelephonyManager#NETWORK_TYPE_*}.
+     */
+    // TODO: 1. Consider move this to TelephonyManager if used by other modules.
+    //       2. Consider make this configurable.
+    //       3. Use TelephonyManager APIs when available.
+    public static int getCollapsedRatType(int ratType) {
+        switch (ratType) {
+            case TelephonyManager.NETWORK_TYPE_GPRS:
+            case TelephonyManager.NETWORK_TYPE_GSM:
+            case TelephonyManager.NETWORK_TYPE_EDGE:
+            case TelephonyManager.NETWORK_TYPE_IDEN:
+            case TelephonyManager.NETWORK_TYPE_CDMA:
+            case TelephonyManager.NETWORK_TYPE_1xRTT:
+                return TelephonyManager.NETWORK_TYPE_GSM;
+            case TelephonyManager.NETWORK_TYPE_EVDO_0:
+            case TelephonyManager.NETWORK_TYPE_EVDO_A:
+            case TelephonyManager.NETWORK_TYPE_EVDO_B:
+            case TelephonyManager.NETWORK_TYPE_EHRPD:
+            case TelephonyManager.NETWORK_TYPE_UMTS:
+            case TelephonyManager.NETWORK_TYPE_HSDPA:
+            case TelephonyManager.NETWORK_TYPE_HSUPA:
+            case TelephonyManager.NETWORK_TYPE_HSPA:
+            case TelephonyManager.NETWORK_TYPE_HSPAP:
+            case TelephonyManager.NETWORK_TYPE_TD_SCDMA:
+                return TelephonyManager.NETWORK_TYPE_UMTS;
+            case TelephonyManager.NETWORK_TYPE_LTE:
+            case TelephonyManager.NETWORK_TYPE_IWLAN:
+                return TelephonyManager.NETWORK_TYPE_LTE;
+            case TelephonyManager.NETWORK_TYPE_NR:
+                return TelephonyManager.NETWORK_TYPE_NR;
+            default:
+                return TelephonyManager.NETWORK_TYPE_UNKNOWN;
+        }
+    }
+
     /**
      * Check if matches Wi-Fi network template.
      */