Add API for detection of 'closing' mode

Test: build
Change-Id: Ic8b3193a1e5d0475e875cd06881c2d21295cdd0f

libs/WindowManager/Shell/shared/src/com/android/wm/shell/shared/TransitionUtil.java

@@ -69,7 +69,7 @@ public class TransitionUtil {
 
     /** Returns {@code true} if the transition is opening or closing mode. */
     public static boolean isOpenOrCloseMode(@TransitionInfo.TransitionMode int mode) {
-        return isOpeningMode(mode) || mode == TRANSIT_CLOSE || mode == TRANSIT_TO_BACK;
+        return isOpeningMode(mode) || isClosingMode(mode);
     }
 
     /** Returns {@code true} if the transition is opening mode. */
@@ -77,6 +77,11 @@ public class TransitionUtil {
         return mode == TRANSIT_OPEN || mode == TRANSIT_TO_FRONT;
     }
 
+    /** Returns {@code true} if the transition is closing mode. */
+    public static boolean isClosingMode(@TransitionInfo.TransitionMode int mode) {
+        return mode == TRANSIT_CLOSE || mode == TRANSIT_TO_BACK;
+    }
+
     /** Returns {@code true} if the transition has a display change. */
     public static boolean hasDisplayChange(@NonNull TransitionInfo info) {
         for (int i = info.getChanges().size() - 1; i >= 0; --i) {