Merge "Don't dismiss split during enter if already visible" into udc-dev am: 1f23db5438 am: 0a3a98a1f7

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23599662

Change-Id: I5eb577cdd9b5e44bc1eb64661b55dc7c6d7708e4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

libs/WindowManager/Shell/src/com/android/wm/shell/splitscreen/StageCoordinator.java

@@ -1516,6 +1516,10 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
             // Legacy transition we need to create divider here, shell transition case we will
             // create it on #finishEnterSplitScreen
             mSplitLayout.init();
+        } else {
+            // We handle split visibility itself on shell transition, but sometimes we didn't
+            // reset it correctly after dismiss by some reason, so just set invisible before active.
+            setSplitsVisible(false);
         }
         if (taskInfo != null) {
             setSideStagePosition(startPosition, wct);
@@ -2654,11 +2658,11 @@ public class StageCoordinator implements SplitLayout.SplitLayoutHandler,
 
         if (mSplitTransitions.mPendingEnter.mExtraTransitType
                 == TRANSIT_SPLIT_SCREEN_OPEN_TO_SIDE) {
+            // Open to side should only be used when split already active and foregorund.
             if (mainChild == null && sideChild == null) {
                 Log.w(TAG, "Launched a task in split, but didn't receive any task in transition.");
-                mSplitTransitions.mPendingEnter.cancel((cancelWct, cancelT)
-                        -> prepareExitSplitScreen(STAGE_TYPE_UNDEFINED, cancelWct));
-                mSplitUnsupportedToast.show();
+                // This should happen when the target app is already on front, so just cancel.
+                mSplitTransitions.mPendingEnter.cancel(null);
                 return true;
             }
         } else {