* Create DisplayHistory
* Change arguments for _setContentTermsOrKanji
* Set up history-driven content updates
* Use new history only
* Load definitions if missing
* Refactor definitions getting
* Add support for wildcards
* Move definitions setup
* Add events
* Allow state change even if there is no history state
* Update search page to use history
* Fix history overwriting
* Fix search page not seeing state chang events during prepare
* Update state if necessary
* Don't reassign query text if the same
* Remove DisplayContext
* Initialize with real history state
* Track URL
* Update DisplayHistory to support pseudo-history
* Configure history settings on search page
* Fix state
* Use full URL
* Change data format of setContent
* Rename details to content
* Update event arguments
* Fix animation
* Remove old state changes
* Clear content properly
* Remove set/clear content overrides
* Fix setting up event listeners for content clear
* Make clearContent private
* Make focus opt-in
* Validate source
* Add unloaded type
* Generalize content params
* Update how extension unload content is assigned
* Restore query blurring
