[Sync] Cleanup code related to bookmark creation

This patch removes obsolete code which checks that bookmark_node is created.
CreateBookmarkNodeFromSpecifics guarantees that the node will be always
created.

Bug: 1050776
Change-Id: I786e061644928548b859c38cb8ddf3550234503d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2089736Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Commit-Queue: Rushan Suleymanov <rushans@google.com>
Cr-Commit-Position: refs/heads/master@{#747626}

components/sync_bookmarks/bookmark_remote_updates_handler.cc

@@ -495,14 +495,7 @@ bool BookmarkRemoteUpdatesHandler::ProcessCreate(
           ComputeChildNodeIndex(parent_node, update_entity.unique_position,
                                 bookmark_tracker_),
           update_entity.is_folder, bookmark_model_, favicon_service_);
-  if (!bookmark_node) {
-    // We ignore bookmarks we can't add.
-    DLOG(ERROR) << "Failed to create bookmark node with title "
-                << update_entity.specifics.bookmark().title() << " and url "
-                << update_entity.specifics.bookmark().url();
-    LogProblematicBookmark(RemoteBookmarkUpdateError::kCreationFailure);
-    return false;
-  }
+  DCHECK(bookmark_node);
   bookmark_tracker_->Add(update_entity.id, bookmark_node,
                          update.response_version, update_entity.creation_time,
                          update_entity.unique_position,