Fix a few weird state issues from race-conditions

- When starting another transition while the dock transition
is already set, always override that because that transition
starts prolonged animations which will never be ended.
- Only dock if we get a good UP event.

Bug: 28257206
Change-Id: Icabfcf475f419696d2bcff8fbb53cf3b29dedd69

packages/SystemUI/src/com/android/systemui/recents/views/RecentsViewTouchHandler.java

@@ -202,8 +202,8 @@ public class RecentsViewTouchHandler {
      * Handles dragging touch events
      */
     private void handleTouchEvent(MotionEvent ev) {
-        int action = ev.getAction();
-        switch (action & MotionEvent.ACTION_MASK) {
+        int action = ev.getActionMasked();
+        switch (action) {
             case MotionEvent.ACTION_DOWN:
                 mDownPos.set((int) ev.getX(), (int) ev.getY());
                 break;
@@ -258,7 +258,7 @@ public class RecentsViewTouchHandler {
             case MotionEvent.ACTION_CANCEL: {
                 if (mDragRequested) {
                     EventBus.getDefault().send(new DragEndEvent(mDragTask, mTaskView,
-                            mLastDropTarget));
+                            action == MotionEvent.ACTION_UP ? mLastDropTarget : null));
                     break;
                 }
             }

services/core/java/com/android/server/wm/AppTransition.java

@@ -1914,6 +1914,14 @@ public class AppTransition implements Dump {
                 setAppTransition(transit);
             }
         }
+        if (transit != TRANSIT_DOCK_TASK_FROM_RECENTS
+                && mNextAppTransition == TRANSIT_DOCK_TASK_FROM_RECENTS) {
+
+            // Somebody is trying to start another transition while we are waiting for the docking
+            // window to be drawn. Because TRANSIT_DOCK_TASK_FROM_RECENTS starts prolonged
+            // animations, we need to override it or our prolonged animations will never be ended.
+            setAppTransition(transit);
+        }
         boolean prepared = prepare();
         if (isTransitionSet()) {
             mService.mH.removeMessages(H.APP_TRANSITION_TIMEOUT);