• Bug 720304 - Limit number of processed history records, with a hard limit of 500 history items per request.
• Bug 723235 - Request history items sorted by sortindex/frecency.
• Bug 723240 - Request bookmark items sorted by sortindex/frecency.
And imposes a sanity limit of 5,000 bookmarks per fetch.
(Note that batching is outside the scope of these bugs.)