Clean up accessibility gestures.

Closing two small holes in the implementation:
1. The gesture was dispatched before the callback was registered. It
was possible for gestures that failed quickly to fail to report any
status.
2. Gestures could be dispatched before the input filter was
installed. Adding a wait to give the filter a chance to install
before reporting a failure.

Also removing an unused method on the input filter.

Change-Id: I77cd80dcd2cec6c72b3761169aba5eaecf62250b

core/java/android/accessibilityservice/AccessibilityService.java

@@ -624,8 +624,7 @@ public abstract class AccessibilityService extends Service {
                 gesture, 100);
         try {
             synchronized (mLock) {
-                connection.sendMotionEvents(++mGestureStatusCallbackSequence,
-                        new ParceledListSlice<>(events));
+                mGestureStatusCallbackSequence++;
                 if (callback != null) {
                     if (mGestureStatusCallbackInfos == null) {
                         mGestureStatusCallbackInfos = new SparseArray<>();
@@ -634,6 +633,8 @@ public abstract class AccessibilityService extends Service {
                             callback, handler);
                     mGestureStatusCallbackInfos.put(mGestureStatusCallbackSequence, callbackInfo);
                 }
+                connection.sendMotionEvents(mGestureStatusCallbackSequence,
+                        new ParceledListSlice<>(events));
             }
         } catch (RemoteException re) {
             throw new RuntimeException(re);

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

@@ -200,10 +200,6 @@ class AccessibilityInputFilter extends InputFilter implements EventStreamTransfo
         }
     }
 
-    public MotionEventInjector getMotionEventInjector() {
-        return mMotionEventInjector;
-    }
-
     /**
      * Gets current event stream state associated with an input event.
      * @return The event stream state that should be used for the event. Null if the event should

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

@@ -129,6 +129,10 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
 
     private static final int WAIT_WINDOWS_TIMEOUT_MILLIS = 5000;
 
+    // TODO: Restructure service initialization so services aren't connected before all of
+    //       their capabilities are ready.
+    private static final int WAIT_MOTION_INJECTOR_TIMEOUT_MILLIS = 1000;
+
     private static final String FUNCTION_REGISTER_UI_TEST_AUTOMATION_SERVICE =
         "registerUiTestAutomationService";
 
@@ -794,6 +798,8 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
     void setMotionEventInjector(MotionEventInjector motionEventInjector) {
         synchronized (mLock) {
             mMotionEventInjector = motionEventInjector;
+            // We may be waiting on this object being set
+            mLock.notifyAll();
         }
     }
 
@@ -2655,10 +2661,24 @@ public class AccessibilityManagerService extends IAccessibilityManager.Stub {
         @Override
         public void sendMotionEvents(int sequence, ParceledListSlice events) {
             synchronized (mLock) {
-                if (mSecurityPolicy.canPerformGestures(this) && (mMotionEventInjector != null)) {
-                    mMotionEventInjector.injectEvents((List<MotionEvent>) events.getList(),
-                            mServiceInterface, sequence);
-                    return;
+                if (mSecurityPolicy.canPerformGestures(this)) {
+                    final long endMillis =
+                            SystemClock.uptimeMillis() + WAIT_MOTION_INJECTOR_TIMEOUT_MILLIS;
+                    while ((mMotionEventInjector == null)
+                            && (SystemClock.uptimeMillis() < endMillis)) {
+                        try {
+                            mLock.wait(endMillis - SystemClock.uptimeMillis());
+                        } catch (InterruptedException ie) {
+                            /* ignore */
+                        }
+                    }
+                    if (mMotionEventInjector != null) {
+                        mMotionEventInjector.injectEvents((List<MotionEvent>) events.getList(),
+                                mServiceInterface, sequence);
+                        return;
+                    } else {
+                        Slog.e(LOG_TAG, "MotionEventInjector installation timed out");
+                    }
                 }
             }
             try {