[Read Later] Fix crash when adding from the dedicated menu item

There are 2 problems being fixed:
(1) typeSwapBookmarksIfNecessary now stores the type-swapped items
    in a different array. This is the array to search for the new
    bookmark.
(2) sSkipShowSaveFlowForTesting can be null and the if statement
    doesn't account for that.

(cherry picked from commit 237a880)

Bug: 1315511
Change-Id: Iac5c43c847085e4b64e4453540c4c4d6492126ee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3580056
Reviewed-by: bttk - <bttk@chromium.org>
Commit-Queue: Brandon Wylie <wylieb@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#992820}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3594486
Reviewed-by: Krishna Govind <govind@chromium.org>
Commit-Queue: Krishna Govind <govind@chromium.org>
Owners-Override: Krishna Govind <govind@chromium.org>
Cr-Commit-Position: refs/branch-heads/5005@{#62}
Cr-Branched-From: 5b4d945-refs/heads/main@{#992738}

chrome/android/java/src/org/chromium/chrome/browser/read_later/ReadingListUtils.java

@@ -92,11 +92,18 @@ public static boolean maybeTypeSwapAndShowSaveFlow(@NonNull Activity activity,
         // remove the regular bookmark first so the save flow is shown.
         List<BookmarkId> bookmarkIds = new ArrayList<>();
         bookmarkIds.add(bookmarkId);
-        ReadingListUtils.typeSwapBookmarksIfNecessary(bookmarkBridge, bookmarkIds,
-                new ArrayList<>(), bookmarkBridge.getReadingListFolder());
-        if (sSkipShowSaveFlowForTesting) return true;
+        List<BookmarkId> typeSwappedBookmarks = new ArrayList<>();
+        typeSwapBookmarksIfNecessary(bookmarkBridge, bookmarkIds, typeSwappedBookmarks,
+                bookmarkBridge.getReadingListFolder());
+
+        assert typeSwappedBookmarks.size() == 1;
+        if (typeSwappedBookmarks.size() != 1) return false;
+
+        BookmarkId newBookmark = typeSwappedBookmarks.get(0);
+        if (Boolean.TRUE.equals(sSkipShowSaveFlowForTesting)) return true;
         BookmarkUtils.showSaveFlow(activity, bottomsheetController,
-                /*fromExplicitTrackUi=*/false, bookmarkIds.get(0), /*wasBookmarkMoved=*/true);
+                /*fromExplicitTrackUi=*/false, newBookmark,
+                /*wasBookmarkMoved=*/true);
         return true;
     }