Add @SystemApi registerContentObserverForAllUsers in ContentResolver

Also add ContentObserver#onChange(boolean, Collection, int, UserHandle) so
clients can know the corresponding UserHandle for the notification.

Bug: 203606981
Test: atest CtsContentTestCases and manual testing to verify the observer can get notifications for
all the users.

Change-Id: Icec7e70b71d7de1c15faf1736539f169856304a8

core/api/system-current.txt

@@ -2405,6 +2405,7 @@ package android.content {
     method @NonNull public static java.io.File encodeToFile(@NonNull android.net.Uri);
     method @Nullable @RequiresPermission("android.permission.CACHE_CONTENT") public android.os.Bundle getCache(@NonNull android.net.Uri);
     method @RequiresPermission("android.permission.CACHE_CONTENT") public void putCache(@NonNull android.net.Uri, @Nullable android.os.Bundle);
+    method @RequiresPermission(android.Manifest.permission.INTERACT_ACROSS_USERS_FULL) public final void registerContentObserverForAllUsers(@NonNull android.net.Uri, boolean, @NonNull android.database.ContentObserver);
   }
 
   public abstract class Context {
@@ -3147,6 +3148,14 @@ package android.content.rollback {
 
 }
 
+package android.database {
+
+  public abstract class ContentObserver {
+    method public void onChange(boolean, @NonNull java.util.Collection<android.net.Uri>, int, @NonNull android.os.UserHandle);
+  }
+
+}
+
 package android.debug {
 
   public class AdbManager {

core/java/android/content/ContentResolver.java

@@ -2664,6 +2664,38 @@ public abstract class ContentResolver implements ContentInterface {
                 ContentProvider.getUserIdFromUri(uri, mContext.getUserId()));
     }
 
+    /**
+     * Same as {@link #registerContentObserver(Uri, boolean, ContentObserver)}, but the observer
+     * registered will get content change notifications from all users.
+     * {@link ContentObserver#onChange(boolean, Collection, int, UserHandle)} should be
+     * overwritten to get the corresponding {@link UserHandle} for that notification.
+     *
+     * @param uri                  The URI to watch for changes. This can be a specific row URI,
+     *                             or a base URI for a whole class of content.
+     * @param notifyForDescendants When false, the observer will be notified
+     *                             whenever a change occurs to the exact URI specified by
+     *                             <code>uri</code> or to one of the URI's ancestors in the path
+     *                             hierarchy. When true, the observer will also be notified
+     *                             whenever a change occurs to the URI's descendants in the path
+     *                             hierarchy.
+     * @param observer             The object that receives callbacks when changes occur.
+     * @hide
+     * @see #unregisterContentObserver
+     */
+    @RequiresPermission(android.Manifest.permission.INTERACT_ACROSS_USERS_FULL)
+    @SystemApi
+    public final void registerContentObserverForAllUsers(@NonNull Uri uri,
+            boolean notifyForDescendants,
+            @NonNull ContentObserver observer) {
+        Objects.requireNonNull(uri, "uri");
+        Objects.requireNonNull(observer, "observer");
+        registerContentObserver(
+                ContentProvider.getUriWithoutUserId(uri),
+                notifyForDescendants,
+                observer,
+                UserHandle.USER_ALL);
+    }
+
     /** @hide - designated user version */
     @UnsupportedAppUsage
     public final void registerContentObserver(Uri uri, boolean notifyForDescendents,

core/java/android/database/ContentObserver.java

@@ -18,6 +18,7 @@ package android.database;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.SystemApi;
 import android.annotation.UserIdInt;
 import android.app.compat.CompatChanges;
 import android.compat.annotation.ChangeId;
@@ -188,6 +189,27 @@ public abstract class ContentObserver {
         }
     }
 
+    /**
+     * This method is called when a content change occurs. Includes the changed
+     * content Uris when available.
+     * <p>
+     * Subclasses should override this method to handle content changes. To
+     * ensure correct operation on older versions of the framework that did not
+     * provide richer arguments, applications should implement all overloads.
+     *
+     * @param selfChange True if this is a self-change notification.
+     * @param uris The Uris of the changed content.
+     * @param flags Flags indicating details about this change.
+     * @param user The corresponding {@link UserHandle} for the current notification.
+     *
+     * @hide
+     */
+    @SystemApi
+    public void onChange(boolean selfChange, @NonNull Collection<Uri> uris,
+            @NotifyFlags int flags, @NonNull UserHandle user) {
+        onChange(selfChange, uris, user.getIdentifier());
+    }
+
     /** @hide */
     public void onChange(boolean selfChange, @NonNull Collection<Uri> uris,
             @NotifyFlags int flags, @UserIdInt int userId) {
@@ -197,7 +219,7 @@ public abstract class ContentObserver {
         if (!CompatChanges.isChangeEnabled(ADD_CONTENT_OBSERVER_FLAGS)
                 || android.os.Process.myUid() == android.os.Process.SYSTEM_UID) {
             // Deliver userId through argument to preserve hidden API behavior
-            onChange(selfChange, uris, userId);
+            onChange(selfChange, uris, flags, UserHandle.of(userId));
         } else {
             onChange(selfChange, uris, flags);
         }