Accessibility services that do not accept events are mismanaged.

1. If an accessibility service does not specify that it handles any
   event types it was never added to the list of services while
   the system is bound to it. Since the service is not in the list
   with enabled services we never unbind it, hence it consumes
   resources without doing nothing. This is also semantically
   incorrect because a sevice may not want to receive events while
   handling only gestures.

bug:5648345

Change-Id: Id478a4704cdeeb1729330f6ae4b8ff9e06320952

Author: sganov

services/java/com/android/server/accessibility/AccessibilityManagerService.java

@@ -827,7 +827,7 @@ private void notifyAccessibilityServicesDelayedLocked(AccessibilityEvent event,
     private void tryAddServiceLocked(Service service, int userId) {
         try {
             UserState userState = getUserStateLocked(userId);
-            if (userState.mServices.contains(service) || !service.isConfigured()) {
+            if (userState.mServices.contains(service)) {
                 return;
             }
             service.linkToOwnDeath();
@@ -876,7 +876,7 @@ private boolean tryRemoveServiceLocked(Service service) {
     private boolean canDispathEventLocked(Service service, AccessibilityEvent event,
             int handledFeedbackTypes) {
 
-        if (!service.isConfigured()) {
+        if (!service.canReceiveEvents()) {
             return false;
         }
 
@@ -1192,7 +1192,8 @@ private void handleTouchExplorationGrantedAccessibilityServicesChangedLocked(
 
     private void tryEnableTouchExplorationLocked(final Service service) {
         UserState userState = getUserStateLocked(service.mUserId);
-        if (!userState.mIsTouchExplorationEnabled && service.mRequestTouchExplorationMode) {
+        if (!userState.mIsTouchExplorationEnabled && service.mRequestTouchExplorationMode
+                && service.canReceiveEvents()) {
             final boolean canToggleTouchExploration =
                     userState.mTouchExplorationGrantedServices.contains(service.mComponentName);
             if (!service.mIsAutomation && !canToggleTouchExploration) {
@@ -1205,6 +1206,9 @@ private void tryEnableTouchExplorationLocked(final Service service) {
     }
 
     private void tryDisableTouchExplorationLocked(Service service) {
+        if (!service.canReceiveEvents()) {
+            return;
+        }
         UserState userState = getUserStateLocked(service.mUserId);
         if (userState.mIsTouchExplorationEnabled) {
             final int serviceCount = userState.mServices.size();
@@ -1464,7 +1468,7 @@ public void setDynamicallyConfigurableProperties(AccessibilityServiceInfo info)
             // If this service is up and running we may have to enable touch
             // exploration, otherwise this will happen when the service connects.
             synchronized (mLock) {
-                if (isConfigured()) {
+                if (canReceiveEvents()) {
                     if (mRequestTouchExplorationMode) {
                         tryEnableTouchExplorationLocked(this);
                     } else {
@@ -1505,13 +1509,7 @@ public boolean unbind() {
             return false;
         }
 
-        /**
-         * Returns if the service is configured i.e. at least event types of interest
-         * and feedback type must be set.
-         *
-         * @return True if the service is configured, false otherwise.
-         */
-        public boolean isConfigured() {
+        public boolean canReceiveEvents() {
             return (mEventTypes != 0 && mFeedbackType != 0 && mService != null);
         }