Move the test of minimum supported keepalive slots to CTS

This change also enables log when keepalive is started.

Bug: 134352656
Test: 1. atest android.net.cts.ConnectivityManagerTest#testSocketKeepaliveLimitTelephony
      2. atest FrameworksNetTests
Change-Id: I408750fa0bceb0c1c26afb5fead4e44fb824fbc1

core/java/android/net/util/KeepaliveUtils.java

@@ -34,9 +34,6 @@ public final class KeepaliveUtils {
 
     public static final String TAG = "KeepaliveUtils";
 
-    // Minimum supported keepalive count per transport if the network supports keepalive.
-    public static final int MIN_SUPPORTED_KEEPALIVE_COUNT = 3;
-
     public static class KeepaliveDeviceConfigurationException extends AndroidRuntimeException {
         public KeepaliveDeviceConfigurationException(final String msg) {
             super(msg);
@@ -84,10 +81,7 @@ public final class KeepaliveUtils {
                 throw new KeepaliveDeviceConfigurationException("Invalid transport " + transport);
             }
 
-            // Customized values should be either 0 to indicate the network doesn't support
+            if (supported < 0) {
-            // keepalive offload, or a positive value that is at least
-            // MIN_SUPPORTED_KEEPALIVE_COUNT if supported.
-            if (supported != 0 && supported < MIN_SUPPORTED_KEEPALIVE_COUNT) {
                 throw new KeepaliveDeviceConfigurationException(
                         "Invalid supported count " + supported + " for "
                                 + NetworkCapabilities.transportNameOf(transport));

services/core/java/com/android/server/connectivity/KeepaliveTracker.java

@@ -562,7 +562,7 @@ public class KeepaliveTracker {
         if (KeepaliveInfo.STARTING == ki.mStartedState) {
             if (SUCCESS == reason) {
                 // Keepalive successfully started.
-                if (DBG) Log.d(TAG, "Started keepalive " + slot + " on " + nai.name());
+                Log.d(TAG, "Started keepalive " + slot + " on " + nai.name());
                 ki.mStartedState = KeepaliveInfo.STARTED;
                 try {
                     ki.mCallback.onStarted(slot);

tests/net/java/android/net/util/KeepaliveUtilsTest.kt

@@ -78,7 +78,6 @@ class KeepaliveUtilsTest {
         assertRunWithException(arrayOf("5"))
 
         // Check resource with invalid slots value.
-        assertRunWithException(arrayOf("2,2"))
         assertRunWithException(arrayOf("3,-1"))
 
         // Check resource with invalid transport type.