Extract logging of default network events

This patch extracts the logging of DefaultNetworkEvent from inside
ConnectivityService and move it to a new DefaultNetworkMetrics class.

The DefaultNetworkMetrics is a singleton owned by the
IpConnectivityMetrics singleton implementing the metrics service for
core networking. ConnectivityService has access to this singleton via
LocalServices.

This class layout will allow to remove the Parcelable interface of
DefaultNetworkEvent and will instead let the IpConnectivityMetrics
service grab metrics from the DefaultNetworkMetrics directly.

Bug: 34901696
Test: runtest frameworks-net
Change-Id: I55694d89124272732aba114198776462372de18b

tests/net/java/com/android/server/ConnectivityServiceTest.java

@@ -104,6 +104,8 @@ import android.util.LogPrinter;
 import com.android.internal.util.WakeupMessage;
 import com.android.internal.util.test.BroadcastInterceptingContext;
 import com.android.internal.util.test.FakeSettingsProvider;
+import com.android.server.connectivity.DefaultNetworkMetrics;
+import com.android.server.connectivity.IpConnectivityMetrics;
 import com.android.server.connectivity.MockableSystemProperties;
 import com.android.server.connectivity.NetworkAgentInfo;
 import com.android.server.connectivity.NetworkMonitor;
@@ -156,6 +158,9 @@ public class ConnectivityServiceTest {
     private MockNetworkAgent mEthernetNetworkAgent;
     private Context mContext;
 
+    @Mock IpConnectivityMetrics.Logger mMetricsService;
+    @Mock DefaultNetworkMetrics mDefaultNetworkMetrics;
+
     // This class exists to test bindProcessToNetwork and getBoundNetworkForProcess. These methods
     // do not go through ConnectivityService but talk to netd directly, so they don't automatically
     // reflect the state of our test ConnectivityService.
@@ -805,6 +810,11 @@ public class ConnectivityServiceTest {
             return Context.ETHERNET_SERVICE.equals(name);
         }
 
+        @Override
+        protected IpConnectivityMetrics.Logger metricsLogger() {
+            return mMetricsService;
+        }
+
         public WrappedNetworkMonitor getLastCreatedWrappedNetworkMonitor() {
             return mLastCreatedNetworkMonitor;
         }
@@ -833,6 +843,9 @@ public class ConnectivityServiceTest {
     public void setUp() throws Exception {
         mContext = InstrumentationRegistry.getContext();
 
+        MockitoAnnotations.initMocks(this);
+        when(mMetricsService.defaultNetworkMetrics()).thenReturn(mDefaultNetworkMetrics);
+
         // InstrumentationTestRunner prepares a looper, but AndroidJUnitRunner does not.
         // http://b/25897652 .
         if (Looper.myLooper() == null) {