Implemented advanced printer selection and API refactoring.

1. Added past printer history tracking and merging favorite printers
   with discovered printers.

2. Added save as PDF support.

3. Added all printers activity with search capability and optional
   add printers chooser (if any print service provides add printers
   activity)

4. Refactored the printer discovery session APIs. Now one session
   can have multiple window discovery windows and the session stores
   the printers found during past discovery periods.

5. Merged the print spooler and the print spooler service - much
   simpler and easier to maintain.

Change-Id: I4830b0eb6367e1c748b768a5ea9ea11baf36cfad

3 files changed, 416 insertions, 79 deletions

diff --git a/services/java/com/android/server/print/RemotePrintService.java b/services/java/com/android/server/print/RemotePrintService.java
index 491dddc..5c68460 100644
--- a/services/java/com/android/server/print/RemotePrintService.java
+++ b/services/java/com/android/server/print/RemotePrintService.java
@@ -30,8 +30,6 @@ import android.os.Message;
 import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
 import android.os.UserHandle;
-import android.print.IPrinterDiscoverySessionController;
-import android.print.IPrinterDiscoverySessionObserver;
 import android.print.PrintJobInfo;
 import android.print.PrintManager;
 import android.print.PrinterId;
@@ -79,6 +77,10 @@ final class RemotePrintService implements DeathRecipient {
 
     private boolean mDestroyed;
 
+    private boolean mAllPrintJobsHandled;
+
+    private boolean mHasPrinterDiscoverySession;
+
     public RemotePrintService(Context context, ComponentName componentName, int userId,
             RemotePrintSpooler spooler) {
         mContext = context;
@@ -97,6 +99,8 @@ final class RemotePrintService implements DeathRecipient {
     private void handleDestroy() {
         throwIfDestroyed();
         ensureUnbound();
+        mAllPrintJobsHandled = false;
+        mHasPrinterDiscoverySession = false;
         mDestroyed = true;
     }
 
@@ -110,18 +114,27 @@ final class RemotePrintService implements DeathRecipient {
     }
 
     private void handleBinderDied() {
+        mAllPrintJobsHandled = false;
+        mHasPrinterDiscoverySession = false;
         mPendingCommands.clear();
         ensureUnbound();
     }
 
     private void handleOnAllPrintJobsHandled() {
         throwIfDestroyed();
+
+        mAllPrintJobsHandled = true;
+
         if (isBound()) {
             if (DEBUG) {
                 Slog.i(LOG_TAG, "[user: " + mUserId + "] handleOnAllPrintJobsHandled()");
             }
-            // If bound and all the work is completed, then unbind.
-            ensureUnbound();
+
+            // If the service has a printer discovery session
+            // created we should not disconnect from it just yet.
+            if (!mHasPrinterDiscoverySession) {
+                ensureUnbound();
+            }
         }
     }
 
@@ -153,6 +166,9 @@ final class RemotePrintService implements DeathRecipient {
 
     private void handleOnPrintJobQueued(final PrintJobInfo printJob) {
         throwIfDestroyed();
+
+        mAllPrintJobsHandled = false;
+
         if (!isBound()) {
             ensureBound();
             mPendingCommands.add(new Runnable() {
@@ -173,20 +189,18 @@ final class RemotePrintService implements DeathRecipient {
         }
     }
 
-    public void createPrinterDiscoverySession(IPrinterDiscoverySessionObserver observer) {
-        mHandler.obtainMessage(MyHandler.MSG_CREATE_PRINTER_DISCOVERY_SESSION,
-                observer).sendToTarget();
+    public void createPrinterDiscoverySession() {
+        mHandler.sendEmptyMessage(MyHandler.MSG_CREATE_PRINTER_DISCOVERY_SESSION);
     }
 
-    private void handleCreatePrinterDiscoverySession(
-            final IPrinterDiscoverySessionObserver observer) {
+    private void handleCreatePrinterDiscoverySession() {
         throwIfDestroyed();
         if (!isBound()) {
             ensureBound();
             mPendingCommands.add(new Runnable() {
                 @Override
                 public void run() {
-                    handleCreatePrinterDiscoverySession(observer);
+                    handleCreatePrinterDiscoverySession();
                 }
             });
         } else {
@@ -194,9 +208,126 @@ final class RemotePrintService implements DeathRecipient {
                 Slog.i(LOG_TAG, "[user: " + mUserId + "] createPrinterDiscoverySession()");
             }
             try {
-                mPrintService.createPrinterDiscoverySession(observer);
+                mPrintService.createPrinterDiscoverySession();
+            } catch (RemoteException re) {
+                Slog.e(LOG_TAG, "Error creating printer dicovery session.", re);
+            }
+
+            mHasPrinterDiscoverySession = true;
+        }
+    }
+
+    public void destroyPrinterDiscoverySession() {
+        mHandler.sendEmptyMessage(MyHandler.MSG_DESTROY_PRINTER_DISCOVERY_SESSION);
+    }
+
+    private void handleDestroyPrinterDiscoverySession() {
+        throwIfDestroyed();
+        if (!isBound()) {
+            ensureBound();
+            mPendingCommands.add(new Runnable() {
+                @Override
+                public void run() {
+                    handleDestroyPrinterDiscoverySession();
+                }
+            });
+        } else {
+            if (DEBUG) {
+                Slog.i(LOG_TAG, "[user: " + mUserId + "] destroyPrinterDiscoverySession()");
+            }
+
+            mHasPrinterDiscoverySession = false;
+
+            try {
+                mPrintService.destroyPrinterDiscoverySession();
+            } catch (RemoteException re) {
+                Slog.e(LOG_TAG, "Error destroying printer dicovery session.", re);
+            }
+
+            // If the service has no print jobs and no active discovery
+            // session anymore we should disconnect from it.
+            if (mAllPrintJobsHandled) {
+                ensureUnbound();
+            }
+        }
+    }
+
+    public void startPrinterDiscovery(List<PrinterId> priorityList) {
+        mHandler.obtainMessage(MyHandler.MSG_START_PRINTER_DISCOVERY,
+                priorityList).sendToTarget();
+    }
+
+    private void handleStartPrinterDiscovery(final List<PrinterId> priorityList) {
+        throwIfDestroyed();
+        if (!isBound()) {
+            ensureBound();
+            mPendingCommands.add(new Runnable() {
+                @Override
+                public void run() {
+                    handleStartPrinterDiscovery(priorityList);
+                }
+            });
+        } else {
+            if (DEBUG) {
+                Slog.i(LOG_TAG, "[user: " + mUserId + "] startPrinterDiscovery()");
+            }
+            try {
+                mPrintService.startPrinterDiscovery(priorityList);
+            } catch (RemoteException re) {
+                Slog.e(LOG_TAG, "Error starting printer dicovery.", re);
+            }
+        }
+    }
+
+    public void stopPrinterDiscovery() {
+        mHandler.sendEmptyMessage(MyHandler.MSG_STOP_PRINTER_DISCOVERY);
+    }
+
+    private void handleStopPrinterDiscovery() {
+        throwIfDestroyed();
+        if (!isBound()) {
+            ensureBound();
+            mPendingCommands.add(new Runnable() {
+                @Override
+                public void run() {
+                    handleStopPrinterDiscovery();
+                }
+            });
+        } else {
+            if (DEBUG) {
+                Slog.i(LOG_TAG, "[user: " + mUserId + "] stopPrinterDiscovery()");
+            }
+            try {
+                mPrintService.stopPrinterDiscovery();
             } catch (RemoteException re) {
-                Slog.e(LOG_TAG, "Error announcing start printer dicovery.", re);
+                Slog.e(LOG_TAG, "Error stopping printer dicovery.", re);
+            }
+        }
+    }
+
+    public void requestPrinterUpdate(PrinterId printerId) {
+        mHandler.obtainMessage(MyHandler.MSG_REQUEST_PRINTER_UPDATE,
+                printerId).sendToTarget();
+    }
+
+    private void handleRequestPrinterUpdate(final PrinterId printerId) {
+        throwIfDestroyed();
+        if (!isBound()) {
+            ensureBound();
+            mPendingCommands.add(new Runnable() {
+                @Override
+                public void run() {
+                    handleRequestPrinterUpdate(printerId);
+                }
+            });
+        } else {
+            if (DEBUG) {
+                Slog.i(LOG_TAG, "[user: " + mUserId + "] requestPrinterUpdate()");
+            }
+            try {
+                mPrintService.requestPrinterUpdate(printerId);
+            } catch (RemoteException re) {
+                Slog.e(LOG_TAG, "Error requesting a printer update.", re);
             }
         }
     }
@@ -279,20 +410,47 @@ final class RemotePrintService implements DeathRecipient {
     }
 
     private final class MyHandler extends Handler {
-        public static final int MSG_ON_ALL_PRINT_JOBS_HANDLED = 1;
-        public static final int MSG_ON_REQUEST_CANCEL_PRINT_JOB = 2;
-        public static final int MSG_ON_PRINT_JOB_QUEUED = 3;
-        public static final int MSG_CREATE_PRINTER_DISCOVERY_SESSION = 4;
-        public static final int MSG_DESTROY = 6;
-        public static final int MSG_BINDER_DIED = 7;
+        public static final int MSG_CREATE_PRINTER_DISCOVERY_SESSION = 1;
+        public static final int MSG_DESTROY_PRINTER_DISCOVERY_SESSION = 2;
+        public static final int MSG_START_PRINTER_DISCOVERY = 3;
+        public static final int MSG_STOP_PRINTER_DISCOVERY = 4;
+        public static final int MSG_REQUEST_PRINTER_UPDATE = 5;
+        public static final int MSG_ON_ALL_PRINT_JOBS_HANDLED = 6;
+        public static final int MSG_ON_REQUEST_CANCEL_PRINT_JOB = 7;
+        public static final int MSG_ON_PRINT_JOB_QUEUED = 8;
+        public static final int MSG_DESTROY = 9;
+        public static final int MSG_BINDER_DIED = 10;
 
         public MyHandler(Looper looper) {
             super(looper, null, false);
         }
 
         @Override
+        @SuppressWarnings("unchecked")
         public void handleMessage(Message message) {
             switch (message.what) {
+                case MSG_CREATE_PRINTER_DISCOVERY_SESSION: {
+                    handleCreatePrinterDiscoverySession();
+                } break;
+
+                case MSG_DESTROY_PRINTER_DISCOVERY_SESSION: {
+                    handleDestroyPrinterDiscoverySession();
+                } break;
+
+                case MSG_START_PRINTER_DISCOVERY: {
+                    List<PrinterId> priorityList = (ArrayList<PrinterId>) message.obj;
+                    handleStartPrinterDiscovery(priorityList);
+                } break;
+
+                case MSG_STOP_PRINTER_DISCOVERY: {
+                    handleStopPrinterDiscovery();
+                } break;
+
+                case MSG_REQUEST_PRINTER_UPDATE: {
+                    PrinterId printerId = (PrinterId) message.obj;
+                    handleRequestPrinterUpdate(printerId);
+                } break;
+
                 case MSG_ON_ALL_PRINT_JOBS_HANDLED: {
                     handleOnAllPrintJobsHandled();
                 } break;
@@ -307,13 +465,6 @@ final class RemotePrintService implements DeathRecipient {
                     handleOnPrintJobQueued(printJob);
                 } break;
 
-                case MSG_CREATE_PRINTER_DISCOVERY_SESSION: {
-                    IPrinterDiscoverySessionObserver observer =
-                            (IPrinterDiscoverySessionObserver) message.obj;
-                    handleCreatePrinterDiscoverySession(new SecurePrinterDiscoverySessionObserver(
-                            mComponentName, observer));
-                } break;
-
                 case MSG_DESTROY: {
                     handleDestroy();
                 } break;
@@ -363,7 +514,7 @@ final class RemotePrintService implements DeathRecipient {
         }
 
         @Override
-        public boolean setPrintJobState(int printJobId, int state, CharSequence error) {
+        public boolean setPrintJobState(int printJobId, int state, String error) {
             RemotePrintService service = mWeakService.get();
             if (service != null) {
                 final long identity = Binder.clearCallingIdentity();
@@ -402,79 +553,70 @@ final class RemotePrintService implements DeathRecipient {
                 }
             }
         }
-    }
-
-    private static final class SecurePrinterDiscoverySessionObserver
-            extends IPrinterDiscoverySessionObserver.Stub {
-        private final ComponentName mComponentName;
-
-        private final IPrinterDiscoverySessionObserver mDecoratedObsever;
-
-        public SecurePrinterDiscoverySessionObserver(ComponentName componentName,
-                IPrinterDiscoverySessionObserver observer) {
-            mComponentName = componentName;
-            mDecoratedObsever = observer;
-        }
 
         @Override
         public void onPrintersAdded(List<PrinterInfo> printers) {
-            throwIfPrinterIdsForPrinterInfoTampered(printers);
-            try {
-                mDecoratedObsever.onPrintersAdded(printers);
-            } catch (RemoteException re) {
-                Slog.e(LOG_TAG, "Error delegating to onPrintersAdded", re);
-            }
-        }
-
-        @Override
-        public void onPrintersUpdated(List<PrinterInfo> printers) {
-            throwIfPrinterIdsForPrinterInfoTampered(printers);
-            try {
-                mDecoratedObsever.onPrintersUpdated(printers);
-            } catch (RemoteException re) {
-                Slog.e(LOG_TAG, "Error delegating to onPrintersUpdated.", re);
+            RemotePrintService service = mWeakService.get();
+            if (service != null) {
+                throwIfPrinterIdsForPrinterInfoTampered(service.mComponentName, printers);
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    service.mSpooler.onPrintersAdded(printers);
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                }
             }
         }
 
         @Override
         public void onPrintersRemoved(List<PrinterId> printerIds) {
-            throwIfPrinterIdsTampered(printerIds);
-            try {
-                mDecoratedObsever.onPrintersRemoved(printerIds);
-            } catch (RemoteException re) {
-                Slog.e(LOG_TAG, "Error delegating to onPrintersRemoved", re);
+            RemotePrintService service = mWeakService.get();
+            if (service != null) {
+                throwIfPrinterIdsTampered(service.mComponentName, printerIds);
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    service.mSpooler.onPrintersRemoved(printerIds);
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                }
             }
         }
 
         @Override
-        public void setController(IPrinterDiscoverySessionController controller) {
-            try {
-                mDecoratedObsever.setController(controller);
-            } catch (RemoteException re) {
-                Slog.e(LOG_TAG, "Error setting controller", re);
+        public void onPrintersUpdated(List<PrinterInfo> printers) {
+            RemotePrintService service = mWeakService.get();
+            if (service != null) {
+                throwIfPrinterIdsForPrinterInfoTampered(service.mComponentName, printers);
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    service.mSpooler.onPrintersUpdated(printers);
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                }
             }
         }
 
-        private void throwIfPrinterIdsForPrinterInfoTampered(
+        private void throwIfPrinterIdsForPrinterInfoTampered(ComponentName serviceName,
                 List<PrinterInfo> printerInfos) {
             final int printerInfoCount = printerInfos.size();
             for (int i = 0; i < printerInfoCount; i++) {
                 PrinterId printerId = printerInfos.get(i).getId();
-                throwIfPrinterIdTampered(printerId);
+                throwIfPrinterIdTampered(serviceName, printerId);
             }
         }
 
-        private void throwIfPrinterIdsTampered(List<PrinterId> printerIds) {
+        private void throwIfPrinterIdsTampered(ComponentName serviceName,
+                List<PrinterId> printerIds) {
             final int printerIdCount = printerIds.size();
             for (int i = 0; i < printerIdCount; i++) {
                 PrinterId printerId = printerIds.get(i);
-                throwIfPrinterIdTampered(printerId);
+                throwIfPrinterIdTampered(serviceName, printerId);
             }
         }
 
-        private void throwIfPrinterIdTampered(PrinterId printerId) {
+        private void throwIfPrinterIdTampered(ComponentName serviceName, PrinterId printerId) {
             if (printerId == null || printerId.getServiceName() == null
-                    || !printerId.getServiceName().equals(mComponentName)) {
+                    || !printerId.getServiceName().equals(serviceName)) {
                 throw new IllegalArgumentException("Invalid printer id: " + printerId);
             }
         }
diff --git a/services/java/com/android/server/print/RemotePrintSpooler.java b/services/java/com/android/server/print/RemotePrintSpooler.java
index c932e9b..d261288 100644
--- a/services/java/com/android/server/print/RemotePrintSpooler.java
+++ b/services/java/com/android/server/print/RemotePrintSpooler.java
@@ -32,9 +32,10 @@ import android.print.IPrintDocumentAdapter;
 import android.print.IPrintSpooler;
 import android.print.IPrintSpoolerCallbacks;
 import android.print.IPrintSpoolerClient;
-import android.print.IPrinterDiscoverySessionObserver;
 import android.print.PrintAttributes;
 import android.print.PrintJobInfo;
+import android.print.PrinterId;
+import android.print.PrinterInfo;
 import android.util.Slog;
 import android.util.TimedRemoteCaller;
 
@@ -92,7 +93,11 @@ final class RemotePrintSpooler {
     public static interface PrintSpoolerCallbacks {
         public void onPrintJobQueued(PrintJobInfo printJob);
         public void onAllPrintJobsForServiceHandled(ComponentName printService);
-        public void createPrinterDiscoverySession(IPrinterDiscoverySessionObserver observer);
+        public void createPrinterDiscoverySession();
+        public void destroyPrinterDiscoverySession();
+        public void startPrinterDiscovery(List<PrinterId> priorityList);
+        public void stopPrinterDiscovery();
+        public void requestPrinterUpdate(PrinterId printerId);
     }
 
     public RemotePrintSpooler(Context context, int userId,
@@ -209,7 +214,7 @@ final class RemotePrintSpooler {
         return null;
     }
 
-    public final boolean setPrintJobState(int printJobId, int state, CharSequence error) {
+    public final boolean setPrintJobState(int printJobId, int state, String error) {
         throwIfCalledOnMainThread();
         synchronized (mLock) {
             throwIfDestroyedLocked();
@@ -300,6 +305,78 @@ final class RemotePrintSpooler {
         }
     }
 
+    public final void onPrintersAdded(List<PrinterInfo> printers) {
+        throwIfCalledOnMainThread();
+        synchronized (mLock) {
+            throwIfDestroyedLocked();
+            mCanUnbind = false;
+        }
+        try {
+            getRemoteInstanceLazy().onPrintersAdded(printers);
+        } catch (RemoteException re) {
+            Slog.e(LOG_TAG, "Error adding printers.", re);
+        } catch (TimeoutException te) {
+            Slog.e(LOG_TAG, "Error adding printers.", te);
+        } finally {
+            if (DEBUG) {
+                Slog.i(LOG_TAG, "[user: " + mUserHandle.getIdentifier()
+                        + "] onPrintersAdded()");
+            }
+            synchronized (mLock) {
+                mCanUnbind = true;
+                mLock.notifyAll();
+            }
+        }
+    }
+
+    public final void onPrintersRemoved(List<PrinterId> printerIds) {
+        throwIfCalledOnMainThread();
+        synchronized (mLock) {
+            throwIfDestroyedLocked();
+            mCanUnbind = false;
+        }
+        try {
+            getRemoteInstanceLazy().onPrintersRemoved(printerIds);
+        } catch (RemoteException re) {
+            Slog.e(LOG_TAG, "Error removing printers.", re);
+        } catch (TimeoutException te) {
+            Slog.e(LOG_TAG, "Error removing printers.", te);
+        } finally {
+            if (DEBUG) {
+                Slog.i(LOG_TAG, "[user: " + mUserHandle.getIdentifier()
+                        + "] onPrintersRemoved()");
+            }
+            synchronized (mLock) {
+                mCanUnbind = true;
+                mLock.notifyAll();
+            }
+        }
+    }
+
+    public final void onPrintersUpdated(List<PrinterInfo> printers) {
+        throwIfCalledOnMainThread();
+        synchronized (mLock) {
+            throwIfDestroyedLocked();
+            mCanUnbind = false;
+        }
+        try {
+            getRemoteInstanceLazy().onPrintersUpdated(printers);
+        } catch (RemoteException re) {
+            Slog.e(LOG_TAG, "Error updating printers.", re);
+        } catch (TimeoutException te) {
+            Slog.e(LOG_TAG, "Error updating printers.", te);
+        } finally {
+            if (DEBUG) {
+                Slog.i(LOG_TAG, "[user: " + mUserHandle.getIdentifier()
+                        + "] onPrintersUpdted()");
+            }
+            synchronized (mLock) {
+                mCanUnbind = true;
+                mLock.notifyAll();
+            }
+        }
+    }
+
     private IPrintSpooler getRemoteInstanceLazy() throws TimeoutException {
         synchronized (mLock) {
             if (mRemoteInstance != null) {
@@ -488,7 +565,7 @@ final class RemotePrintSpooler {
         }
 
         public boolean setPrintJobState(IPrintSpooler target, int printJobId,
-                int status, CharSequence error) throws RemoteException, TimeoutException {
+                int status, String error) throws RemoteException, TimeoutException {
             final int sequence = onBeforeRemoteCall();
             target.setPrintJobState(printJobId, status, error, mCallback, sequence);
             return getResultTimed(sequence);
@@ -597,12 +674,64 @@ final class RemotePrintSpooler {
         }
 
         @Override
-        public void createPrinterDiscoverySession(IPrinterDiscoverySessionObserver observer) {
+        public void createPrinterDiscoverySession() {
+            RemotePrintSpooler spooler = mWeakSpooler.get();
+            if (spooler != null) {
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    spooler.mCallbacks.createPrinterDiscoverySession();
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                }
+            }
+        }
+
+        @Override
+        public void destroyPrinterDiscoverySession() {
+            RemotePrintSpooler spooler = mWeakSpooler.get();
+            if (spooler != null) {
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    spooler.mCallbacks.destroyPrinterDiscoverySession();
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                }
+            }
+        }
+
+        @Override
+        public void startPrinterDiscovery(List<PrinterId> priorityList) {
+            RemotePrintSpooler spooler = mWeakSpooler.get();
+            if (spooler != null) {
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    spooler.mCallbacks.startPrinterDiscovery(priorityList);
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                }
+            }
+        }
+
+        @Override
+        public void stopPrinterDiscovery() {
+            RemotePrintSpooler spooler = mWeakSpooler.get();
+            if (spooler != null) {
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    spooler.mCallbacks.stopPrinterDiscovery();
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
+                }
+            }
+        }
+
+        @Override
+        public void requestPrinterUpdate(PrinterId printerId) {
             RemotePrintSpooler spooler = mWeakSpooler.get();
             if (spooler != null) {
                 final long identity = Binder.clearCallingIdentity();
                 try {
-                    spooler.mCallbacks.createPrinterDiscoverySession(observer);
+                    spooler.mCallbacks.requestPrinterUpdate(printerId);
                 } finally {
                     Binder.restoreCallingIdentity(identity);
                 }
diff --git a/services/java/com/android/server/print/UserState.java b/services/java/com/android/server/print/UserState.java
index ffcc9c3..9d7cfdd 100644
--- a/services/java/com/android/server/print/UserState.java
+++ b/services/java/com/android/server/print/UserState.java
@@ -21,8 +21,8 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
-import android.print.IPrinterDiscoverySessionObserver;
 import android.print.PrintJobInfo;
+import android.print.PrinterId;
 import android.printservice.PrintServiceInfo;
 import android.provider.Settings;
 import android.text.TextUtils;
@@ -105,7 +105,7 @@ final class UserState implements PrintSpoolerCallbacks {
     }
 
     @Override
-    public void createPrinterDiscoverySession(IPrinterDiscoverySessionObserver observer) {
+    public void createPrinterDiscoverySession() {
         final List<RemotePrintService> services;
         synchronized (mLock) {
             throwIfDestroyedLocked();
@@ -117,7 +117,73 @@ final class UserState implements PrintSpoolerCallbacks {
         final int serviceCount = services.size();
         for (int i = 0; i < serviceCount; i++) {
             RemotePrintService service = services.get(i);
-            service.createPrinterDiscoverySession(observer);
+            service.createPrinterDiscoverySession();
+        }
+    }
+
+    @Override
+    public void destroyPrinterDiscoverySession() {
+        final List<RemotePrintService> services;
+        synchronized (mLock) {
+            throwIfDestroyedLocked();
+            if (mActiveServices.isEmpty()) {
+                return;
+            }
+            services = new ArrayList<RemotePrintService>(mActiveServices.values());
+        }
+        final int serviceCount = services.size();
+        for (int i = 0; i < serviceCount; i++) {
+            RemotePrintService service = services.get(i);
+            service.destroyPrinterDiscoverySession();
+        }
+    }
+
+    @Override
+    public void startPrinterDiscovery(List<PrinterId> printerIds) {
+        final List<RemotePrintService> services;
+        synchronized (mLock) {
+            throwIfDestroyedLocked();
+            if (mActiveServices.isEmpty()) {
+                return;
+            }
+            services = new ArrayList<RemotePrintService>(mActiveServices.values());
+        }
+        final int serviceCount = services.size();
+        for (int i = 0; i < serviceCount; i++) {
+            RemotePrintService service = services.get(i);
+            service.startPrinterDiscovery(printerIds);
+        }
+    }
+
+    @Override
+    public void stopPrinterDiscovery() {
+        final List<RemotePrintService> services;
+        synchronized (mLock) {
+            throwIfDestroyedLocked();
+            if (mActiveServices.isEmpty()) {
+                return;
+            }
+            services = new ArrayList<RemotePrintService>(mActiveServices.values());
+        }
+        final int serviceCount = services.size();
+        for (int i = 0; i < serviceCount; i++) {
+            RemotePrintService service = services.get(i);
+            service.stopPrinterDiscovery();
+        }
+    }
+
+    @Override
+    public void requestPrinterUpdate(PrinterId printerId) {
+        final RemotePrintService service;
+        synchronized (mLock) {
+            throwIfDestroyedLocked();
+            if (mActiveServices.isEmpty()) {
+                return;
+            }
+            service = mActiveServices.get(printerId.getServiceName());
+        }
+        if (service != null) {
+            service.requestPrinterUpdate(printerId);
         }
     }