Merge "Completely remove pinned task when starting a new PiP" into tm-dev am: bfbf74aec1

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18175783

Change-Id: Ia99a7f80a8712cf756fe9407b36fa5583c6c5ea4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

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

@@ -1999,7 +1999,10 @@ class RootWindowContainer extends WindowContainer<DisplayContent>
             final Task rootPinnedTask = taskDisplayArea.getRootPinnedTask();
             if (rootPinnedTask != null) {
                 transitionController.collect(rootPinnedTask);
-                rootPinnedTask.dismissPip();
+                // The new ActivityRecord should replace the existing PiP, so it's more desirable
+                // that the old PiP disappears instead of turning to full-screen at the same time,
+                // as the Task#dismissPip is trying to do.
+                removeRootTasksInWindowingModes(WINDOWING_MODE_PINNED);
             }
 
             // Set a transition to ensure that we don't immediately try and update the visibility