In AccessibilityGestureDetector.clear(), dispatch a MotionEvent.ACTION_CLEAR event to mGestureDetector to cancel the ongoing gesture.

b/30706806

Change-Id: I78954e5484d8deda2dadb7c0ae7e05d5c6b734f2

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

@@ -341,6 +341,8 @@ class AccessibilityGestureDetector extends GestureDetector.SimpleOnGestureListen
         mDoubleTapDetected = false;
         mSecondFingerDoubleTap = false;
         mGestureStarted = false;
+        mGestureDetector.onTouchEvent(MotionEvent.obtain(0L, 0L, MotionEvent.ACTION_CANCEL,
+                0.0f, 0.0f, 0));
         cancelGesture();
     }