| clearTouchIdentifier | Clear the touch identifier that tracks which touch stream to pay attention to. This ends the current drag/gesture and allows other pointers to be captured. |
| shouldHandleEvent | Decide whether Blockly should handle or ignore this event. Mouse and touch events require special checks because we only want to deal with one touch stream at a time. All other events should always be handled. |
| getTouchIdentifierFromEvent | Get the pointer identifier from the given event. |
| checkTouchIdentifier | Check whether the pointer identifier on the event matches the current saved identifier. If the current identifier was unset, save the identifier from the event. This starts a drag/gesture, during which pointer events with other identifiers will be silently ignored. |