Add launcher logging of back button

Bug: 127848641
Test: adb shell setprop log.tag.UserEvent VERBOSE, then hit back
Change-Id: I020738280d2e51a8a192e577baf48c0b092f22f6
(cherry picked from commit df7d00328c)

quickstep/recents_ui_overrides/src/com/android/quickstep/FallbackActivityControllerHelper.java

@@ -192,7 +192,11 @@ public final class FallbackActivityControllerHelper implements
 
     @Override
     public int getContainerType() {
-        return LauncherLogProto.ContainerType.SIDELOADED_LAUNCHER;
+        RecentsActivity activity = getCreatedActivity();
+        boolean visible = activity != null && activity.isStarted() && activity.hasWindowFocus();
+        return visible
+                ? LauncherLogProto.ContainerType.SIDELOADED_LAUNCHER
+                : LauncherLogProto.ContainerType.APP;
     }
 
     @Override