(edebug-set-global-break-condition):

(edebug-set-global-break-condition):
Use `read-expression-history'.  Set initial contents only if
`edebug-global-break-condition' is non-nil.  Set histpos to 1
if initial contents is equal to the last history element.
(edebug-set-conditional-breakpoint): Instead of temporarily
prepending the current condition to the history, set initial
contents to the current condition.  Set histpos to 1 if initial
contents is equal to the last history element.