Annotate @SystemApi with required permissions.

Most @SystemApi methods should be protected with system (or higher)
permissions, so annotate common methods with @RequiresPermission to
make automatic verification easier.

Verification is really only relevant when calling into system
services (where permissions checking can happen on the other side of
a Binder call), so annotate managers with the new @SystemService
annotation, which is now automatically documented.

This is purely a docs change; no logic changes are being made.

Test: make -j32 update-api && make -j32 offline-sdk-docs
Bug: 62263906
Change-Id: I2554227202d84465676aa4ab0dd336b5c45fc651

core/java/android/app/usage/NetworkStatsManager.java

@@ -19,6 +19,7 @@ package android.app.usage;
 import static com.android.internal.util.Preconditions.checkNotNull;
 
 import android.annotation.Nullable;
+import android.annotation.SystemService;
 import android.app.usage.NetworkStats.Bucket;
 import android.content.Context;
 import android.net.ConnectivityManager;
@@ -82,6 +83,7 @@ import android.util.Log;
  * the above permission, even to access an app's own data usage, and carrier-privileged apps were
  * not included.
  */
+@SystemService(Context.NETWORK_STATS_SERVICE)
 public class NetworkStatsManager {
     private static final String TAG = "NetworkStatsManager";
     private static final boolean DBG = false;

core/java/android/net/EthernetManager.java

@@ -16,6 +16,7 @@
 
 package android.net;
 
+import android.annotation.SystemService;
 import android.content.Context;
 import android.net.IEthernetManager;
 import android.net.IEthernetServiceListener;
@@ -31,6 +32,7 @@ import java.util.ArrayList;
  *
  * @hide
  */
+@SystemService(Context.ETHERNET_SERVICE)
 public class EthernetManager {
     private static final String TAG = "EthernetManager";
     private static final int MSG_AVAILABILITY_CHANGED = 1000;

core/java/android/net/IpSecManager.java

@@ -18,6 +18,8 @@ package android.net;
 import static com.android.internal.util.Preconditions.checkNotNull;
 
 import android.annotation.NonNull;
+import android.annotation.SystemService;
+import android.content.Context;
 import android.os.Binder;
 import android.os.Bundle;
 import android.os.ParcelFileDescriptor;
@@ -34,12 +36,9 @@ import java.net.Socket;
  * This class contains methods for managing IPsec sessions, which will perform kernel-space
  * encryption and decryption of socket or Network traffic.
  *
- * <p>An IpSecManager may be obtained by calling {@link
- * android.content.Context#getSystemService(String) Context#getSystemService(String)} with {@link
- * android.content.Context#IPSEC_SERVICE Context#IPSEC_SERVICE}
- *
  * @hide
  */
+@SystemService(Context.IPSEC_SERVICE)
 public final class IpSecManager {
     private static final String TAG = "IpSecManager";
 

core/java/android/net/TrafficStats.java

@@ -16,6 +16,7 @@
 
 package android.net;
 
+import android.annotation.RequiresPermission;
 import android.annotation.SystemApi;
 import android.app.DownloadManager;
 import android.app.backup.BackupManager;
@@ -243,6 +244,7 @@ public class TrafficStats {
      * @hide
      */
     @SystemApi
+    @RequiresPermission(android.Manifest.permission.UPDATE_DEVICE_STATS)
     public static void setThreadStatsUid(int uid) {
         NetworkManagementSocketTagger.setThreadSocketStatsUid(uid);
     }
@@ -255,6 +257,7 @@ public class TrafficStats {
      * @hide
      */
     @SystemApi
+    @RequiresPermission(android.Manifest.permission.UPDATE_DEVICE_STATS)
     public static void clearThreadStatsUid() {
         NetworkManagementSocketTagger.setThreadSocketStatsUid(-1);
     }

core/java/android/net/nsd/NsdManager.java

@@ -17,6 +17,7 @@
 package android.net.nsd;
 
 import android.annotation.SdkConstant;
+import android.annotation.SystemService;
 import android.annotation.SdkConstant.SdkConstantType;
 import android.content.Context;
 import android.os.Handler;
@@ -113,11 +114,9 @@ import com.android.internal.util.Protocol;
  * http://www.iana.org/form/ports-service. Existing services can be found at
  * http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml
  *
- * Get an instance of this class by calling {@link android.content.Context#getSystemService(String)
- * Context.getSystemService(Context.NSD_SERVICE)}.
- *
  * {@see NsdServiceInfo}
  */
+@SystemService(Context.NSD_SERVICE)
 public final class NsdManager {
     private static final String TAG = NsdManager.class.getSimpleName();
     private static final boolean DBG = false;