Oh no [he/she/you/etc.] didn't! is a clichéd phrase for expressing disapproval or incredulity at some event or utterance, though the degree of either is variable. Dpending on the delivery and context, it might indicate anything from a mildly humorous observation to genuinely shocked outrage. The corresponding return is Oh yes she did!, also to be delivered theatrically, perhaps with a finger wag, head bob, finger snap (0:22), or other gestures that have been associated with, to use TVTropes' name, the “Sassy Black Woman” character.
It probably cannot be traced to a single point of origin. Surely schoolchildren have debated the question of whether something was or was not done by someone employing this phrasing for some decades. The phenomenon of its affected pronunciation was discussed on LinguistList as far back as November 2004 in the thread "di?nt" (with glottal stop), where it is observed in Northeastern (US) and in African-American Vernacular English, but is not limited to either. Note also that the question of whether di'nt reflects a glottal stop (as in some British accents) or deletion is brought up but not resolved.
As Ben Zimmer writes:
In recent years the exaggeratedly glottalized "Oh no you/he/she di[?]n't"
(as a response of outrage, or mock outrage) has become a hackneyed
catchphrase. My sense is that the expression had its origin in hiphop and
then started turning up on those "trash TV" shows in the late '90s (with
appropriate hand gestures and head-bobbing). From there it became a
source of mockery for white Americans, as in this bit from Saturday Night
Live's "Weekend Update" (April 2002):
Tina Fey: (nods head) Bill Clinton - Bill Clinton revealed in Newsweek that he is getting a new chocolate lab to replace his dog, Buddy. Bill says, with Hillary away in D.C., he just needs another bitch in the house.
Jimmy Fallon: Oh, snap! Oh, yes, you did!
Tina Fey: (gets up from her chair and starts flapping arms) Oh, no! Oh, no, you didn't! Oh, snap! OKAYYYYY! [etc.]
He finds examples from Usenet dating back to the mid-1990s, for instance
Message-ID: <94110.191901SCW112 at psuvm.psu.edu>
In article <1994Apr20.214045.27522 at random.ccs.northeastern.edu>, nickman at ccs.neu.edu (Jeff Nicolai) says:
- Chuck D. from Public Enemy is from a middle class family in Long Island. As an 'oppressed' rapper from the ghetto........ he ain't Shit!!!!
oh no you didn't...
Message-ID: <030895.10035334596.n at frontier.canrem.com>
Da Brat and Latifah are lesbians. Please don't deny it...
UH, oh no you DIDN'T! Latifah I ain't care aboutm but, but tha Brat? That's cold man, that's cold.
If its wider acceptance in the culture also stems from that period, it may be attributable to the popularity of television shows like Martin or In Living Color, where some characters used exaggerated inner-city speech.