Merge "DO NOT MERGE - [ActivityManager] Ensure consistency behavior when a background activity brings another existed activity to front."

services/java/com/android/server/am/ActivityStackSupervisor.java

@@ -1425,6 +1425,7 @@ public final class ActivityStackSupervisor {
             r.resultTo = null;
         }
 
+        boolean switchStackFromBg = false;
         boolean addingToTask = false;
         boolean movedHome = false;
         TaskRecord reuseTask = null;
@@ -1486,6 +1487,11 @@ public final class ActivityStackSupervisor {
                             }
                             options = null;
                         }
+                    } else {
+                        switchStackFromBg = lastStack != targetStack;
+                        if (DEBUG_TASKS) Slog.d(TAG, "Caller " + sourceRecord
+                                    + " is not top task, it may not move " + r
+                                    + " to front, switchStack=" + switchStackFromBg);
                     }
                     // If the caller has requested that the target task be
                     // reset, then do so.
@@ -1593,6 +1599,10 @@ public final class ActivityStackSupervisor {
                         // don't use that intent!)  And for paranoia, make
                         // sure we have correctly resumed the top activity.
                         if (doResume) {
+                            if (switchStackFromBg) {
+                                moveHomeStack(lastStack.isHomeStack());
+                                targetStack = lastStack;
+                            }
                             targetStack.resumeTopActivityLocked(null, options);
                         } else {
                             ActivityOptions.abort(options);