Add DevicePolicyManager.setBackupServiceEnabled as hidden API.

BUG=28628532

Change-Id: I48c3423734e54b6a4d70e58d50c98c3e17790e0d
(based on a8202524608a4fc9178e6b18e13602c5a8abb404)
diff --git a/core/java/android/app/admin/DevicePolicyManager.java b/core/java/android/app/admin/DevicePolicyManager.java
index 688876c..d6a8dd0 100644
--- a/core/java/android/app/admin/DevicePolicyManager.java
+++ b/core/java/android/app/admin/DevicePolicyManager.java
@@ -6493,4 +6493,35 @@
             throw new SecurityException(functionName + " cannot be called on the parent instance");
         }
     }
+
+    /**
+     * @hide
+     * Enable backup service.
+     * <p>This includes all backup and restore mechanisms.
+     * Setting this to {@code false} will make backup service no-op or return empty results.
+     *
+     * <p>There must be only one user on the device, managed by the device owner.
+     * Otherwise a {@link SecurityException} will be thrown.
+     *
+     * <p>Backup service is off by default when device owner is present.
+     */
+    public void setBackupServiceEnabled(@NonNull ComponentName admin, boolean enabled) {
+        try {
+            mService.setBackupServiceEnabled(admin, enabled);
+        } catch (RemoteException re) {
+            throw re.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * @hide
+     * @return {@code true} if backup service is enabled, {@code false} otherwise.
+     */
+    public boolean isBackupServiceEnabled(@NonNull ComponentName admin) {
+        try {
+            return mService.isBackupServiceEnabled(admin);
+        } catch (RemoteException re) {
+            throw re.rethrowFromSystemServer();
+        }
+    }
 }
diff --git a/core/java/android/app/admin/IDevicePolicyManager.aidl b/core/java/android/app/admin/IDevicePolicyManager.aidl
index 1036f04..43c6230 100644
--- a/core/java/android/app/admin/IDevicePolicyManager.aidl
+++ b/core/java/android/app/admin/IDevicePolicyManager.aidl
@@ -305,4 +305,7 @@
     boolean isDeviceProvisioned();
     boolean isDeviceProvisioningConfigApplied();
     void setDeviceProvisioningConfigApplied();
+
+    void setBackupServiceEnabled(in ComponentName admin, boolean enabled);
+    boolean isBackupServiceEnabled(in ComponentName admin);
 }
diff --git a/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java b/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
index 777c0b3..5f431bc 100644
--- a/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
+++ b/services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java
@@ -497,9 +497,9 @@
                 new MonitoringCertNotificationTask().execute(userId);
             }
             if (Intent.ACTION_USER_ADDED.equals(action)) {
-                disableSecurityLoggingIfNotCompliant();
+                disableDeviceOwnerManagedSingleUserFeaturesIfNeeded();
             } else if (Intent.ACTION_USER_REMOVED.equals(action)) {
-                disableSecurityLoggingIfNotCompliant();
+                disableDeviceOwnerManagedSingleUserFeaturesIfNeeded();
                 removeUserData(userHandle);
             } else if (Intent.ACTION_USER_STARTED.equals(action)) {
                 synchronized (DevicePolicyManagerService.this) {
@@ -1712,7 +1712,7 @@
             if (mOwners.hasDeviceOwner()) {
                 mInjector.systemPropertiesSet(PROPERTY_DEVICE_OWNER_PRESENT, "true");
                 Slog.i(LOG_TAG, "Set ro.device_owner property to true");
-                disableSecurityLoggingIfNotCompliant();
+                disableDeviceOwnerManagedSingleUserFeaturesIfNeeded();
                 if (mInjector.securityLogGetLoggingEnabledProperty()) {
                     mSecurityLogMonitor.start();
                 }
@@ -5930,7 +5930,7 @@
         mOwners.clearDeviceOwner();
         mOwners.writeDeviceOwner();
         updateDeviceOwnerLocked();
-        disableSecurityLoggingIfNotCompliant();
+        disableDeviceOwnerManagedSingleUserFeaturesIfNeeded();
         try {
             // Reactivate backup service.
             mInjector.getIBackupManager().setBackupServiceActive(UserHandle.USER_SYSTEM, true);
@@ -8904,10 +8904,12 @@
         return false;
     }
 
-    private synchronized void disableSecurityLoggingIfNotCompliant() {
+    private synchronized void disableDeviceOwnerManagedSingleUserFeaturesIfNeeded() {
         if (!isDeviceOwnerManagedSingleUserDevice()) {
             mInjector.securityLogSetLoggingEnabledProperty(false);
             Slog.w(LOG_TAG, "Security logging turned off as it's no longer a single user device.");
+            setBackupServiceEnabledInternal(false);
+            Slog.w(LOG_TAG, "Backup is off as it's a managed device that has more that one user.");
         }
     }
 
@@ -9208,4 +9210,46 @@
             return false;
         }
     }
+
+    @Override
+    public void setBackupServiceEnabled(ComponentName admin, boolean enabled) {
+        Preconditions.checkNotNull(admin);
+        if (!mHasFeature) {
+            return;
+        }
+        ensureDeviceOwnerManagingSingleUser(admin);
+        setBackupServiceEnabledInternal(enabled);
+    }
+
+    private synchronized void setBackupServiceEnabledInternal(boolean enabled) {
+        long ident = mInjector.binderClearCallingIdentity();
+        try {
+            IBackupManager ibm = mInjector.getIBackupManager();
+            if (ibm != null) {
+                ibm.setBackupServiceActive(UserHandle.USER_SYSTEM, enabled);
+            }
+        } catch (RemoteException e) {
+            throw new IllegalStateException(
+                "Failed " + (enabled ? "" : "de") + "activating backup service.", e);
+        } finally {
+            mInjector.binderRestoreCallingIdentity(ident);
+        }
+    }
+
+    @Override
+    public boolean isBackupServiceEnabled(ComponentName admin) {
+        Preconditions.checkNotNull(admin);
+        if (!mHasFeature) {
+            return true;
+        }
+        synchronized (this) {
+            getActiveAdminForCallerLocked(admin, DeviceAdminInfo.USES_POLICY_DEVICE_OWNER);
+            try {
+                IBackupManager ibm = mInjector.getIBackupManager();
+                return ibm != null && ibm.isBackupServiceActive(UserHandle.USER_SYSTEM);
+            } catch (RemoteException e) {
+                throw new IllegalStateException("Failed requesting backup service state.", e);
+            }
+        }
+    }
 }