Handle duplicate DOWN event

After unlocking the device, an immediate swipe down to reveal the
shade (a very common user journey) can sometimes just directly to the
QS shade variant, instead of showing the expected QQS shade with
notifications. I have been unable to find root cause at this point,
however, I am aware that multiple ACTION_DOWN events are issued in
this case with the same downTime.

To fix, detect this very specific scenario and ignore the touch.

Fixes: 193350347
Test: manual, follow steps in bug (swipe down after unlock)
Change-Id: I84ba92fb0cf981b227afdff15cbe41c09ea56f5d

packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelViewController.java

@@ -3885,6 +3885,9 @@ public class NotificationPanelViewController extends PanelViewController {
     @Override
     protected TouchHandler createTouchHandler() {
         return new TouchHandler() {
+
+            private long mLastTouchDownTime = -1L;
+
             @Override
             public boolean onInterceptTouchEvent(MotionEvent event) {
                 if (mBlockTouches || mQsFullyExpanded && mQs.disallowPanelTouches()) {
@@ -3914,6 +3917,19 @@ public class NotificationPanelViewController extends PanelViewController {
 
             @Override
             public boolean onTouch(View v, MotionEvent event) {
+                if (event.getAction() == MotionEvent.ACTION_DOWN) {
+                    if (event.getDownTime() == mLastTouchDownTime) {
+                        // An issue can occur when swiping down after unlock, where multiple down
+                        // events are received in this handler with identical downTimes. Until the
+                        // source of the issue can be located, detect this case and ignore.
+                        // see b/193350347
+                        Log.w(TAG, "Duplicate down event detected... ignoring");
+                        return true;
+                    }
+                    mLastTouchDownTime = event.getDownTime();
+                }
+
+
                 if (mBlockTouches || (mQsFullyExpanded && mQs != null
                         && mQs.disallowPanelTouches())) {
                     return false;