Make AM#isEnabled() true if any direct a11y connection exists.

Includes @TestApi AM#hasAnyDirectConnection() to improve test
reliability, because directly testing AM#isEnabled() is muddied
by UiAutomation used in the test itself.

Bug: 249164232
Test: atest AccessibilityEndToEndTest
Test: check node tree of a WebView when no real a11y service
      is enabled.
Change-Id: I4931ce316e9f5a956d266b7fd99f0faf00b8cd0d

core/api/test-current.txt

@@ -2961,6 +2961,7 @@ package android.view.accessibility {
 
   public final class AccessibilityManager {
     method @NonNull @RequiresPermission(android.Manifest.permission.MANAGE_ACCESSIBILITY) public java.util.List<java.lang.String> getAccessibilityShortcutTargets(int);
+    method public boolean hasAnyDirectConnection();
   }
 
   public class AccessibilityNodeInfo implements android.os.Parcelable {

core/java/android/view/ViewRootImpl.java

@@ -10499,6 +10499,8 @@ public final class ViewRootImpl implements ViewParent,
             if (mDirectConnectionId == AccessibilityNodeInfo.UNDEFINED_CONNECTION_ID) {
                 mDirectConnectionId = AccessibilityInteractionClient.addDirectConnection(
                         new AccessibilityInteractionConnection(ViewRootImpl.this));
+                // Notify listeners in the app process.
+                mAccessibilityManager.notifyAccessibilityStateChanged();
             }
             return mDirectConnectionId;
         }
@@ -10507,6 +10509,8 @@ public final class ViewRootImpl implements ViewParent,
             if (mDirectConnectionId != AccessibilityNodeInfo.UNDEFINED_CONNECTION_ID) {
                 AccessibilityInteractionClient.removeConnection(mDirectConnectionId);
                 mDirectConnectionId = AccessibilityNodeInfo.UNDEFINED_CONNECTION_ID;
+                // Notify listeners in the app process.
+                mAccessibilityManager.notifyAccessibilityStateChanged();
             }
         }
     }

core/java/android/view/accessibility/AccessibilityInteractionClient.java

@@ -117,6 +117,7 @@ public final class AccessibilityInteractionClient
     // Used to generate connection ids for direct app-process connections. Start sufficiently far
     // enough from the connection ids generated by AccessibilityManagerService.
     private static int sDirectConnectionIdCounter = 1 << 30;
+    private static int sDirectConnectionCount = 0;
 
     /** List of timestamps which indicate the latest time an a11y service receives a scroll event
         from a window, mapping from windowId -> timestamp. */
@@ -272,12 +273,18 @@ public final class AccessibilityInteractionClient
             DirectAccessibilityConnection directAccessibilityConnection =
                     new DirectAccessibilityConnection(connection);
             sConnectionCache.put(connectionId, directAccessibilityConnection);
+            sDirectConnectionCount++;
             // Do not use AccessibilityCache for this connection, since there is no corresponding
             // AccessibilityService to handle cache invalidation events.
             return connectionId;
         }
     }
 
+    /** Check if any {@link DirectAccessibilityConnection} is currently in the connection cache. */
+    public static boolean hasAnyDirectConnection() {
+        return sDirectConnectionCount > 0;
+    }
+
     /**
      * Gets a cached associated with the connection id if available.
      *
@@ -295,6 +302,9 @@ public final class AccessibilityInteractionClient
      */
     public static void removeConnection(int connectionId) {
         synchronized (sConnectionCache) {
+            if (getConnection(connectionId) instanceof DirectAccessibilityConnection) {
+                sDirectConnectionCount--;
+            }
             sConnectionCache.remove(connectionId);
             sCaches.remove(connectionId);
         }

core/java/android/view/accessibility/AccessibilityManager.java

@@ -602,11 +602,20 @@ public final class AccessibilityManager {
      */
     public boolean isEnabled() {
         synchronized (mLock) {
-            return mIsEnabled || (mAccessibilityPolicy != null
-                    && mAccessibilityPolicy.isEnabled(mIsEnabled));
+            return mIsEnabled || hasAnyDirectConnection()
+                    || (mAccessibilityPolicy != null && mAccessibilityPolicy.isEnabled(mIsEnabled));
         }
     }
 
+    /**
+     * @see AccessibilityInteractionClient#hasAnyDirectConnection
+     * @hide
+     */
+    @TestApi
+    public boolean hasAnyDirectConnection() {
+        return AccessibilityInteractionClient.hasAnyDirectConnection();
+    }
+
     /**
      * Returns if the touch exploration in the system is enabled.
      * <p>
@@ -1942,8 +1951,13 @@ public final class AccessibilityManager {
 
     /**
      * Notifies the registered {@link AccessibilityStateChangeListener}s.
+     *
+     * Note: this method notifies only the listeners of this single instance.
+     * AccessibilityManagerService is responsible for calling this method on all of
+     * its AccessibilityManager clients in order to notify all listeners.
+     * @hide
      */
-    private void notifyAccessibilityStateChanged() {
+    public void notifyAccessibilityStateChanged() {
         final boolean isEnabled;
         final ArrayMap<AccessibilityStateChangeListener, Handler> listeners;
         synchronized (mLock) {