[DO NOT MERGE] MultiFingerSwipe: scale touch slop to number of fingers.

Bug: 162521649
Test: manual
Change-Id: I990693ac07f4653f7d8ff9c097b5720593235afb

services/accessibility/java/com/android/server/accessibility/gestures/MultiFingerSwipe.java

@@ -294,7 +294,7 @@ class MultiFingerSwipe extends GestureMatcher {
                                 + Float.toString(mGestureDetectionThresholdPixels));
             }
             if (getState() == STATE_CLEAR) {
-                if (moveDelta < mTouchSlop) {
+                if (moveDelta < (mTargetFingerCount * mTouchSlop)) {
                     // This still counts as a touch not a swipe.
                     continue;
                 } else if (mStrokeBuffers[pointerIndex].size() == 0) {