GPT Managed OutOfPage ad slots iframe is not resized

[danielguedesb]

Type of issue

bug

Description

Using GPT Managed interstitial slots (https://developers.google.com/publisher-tag/samples/display-web-interstitial-ad), prebid's creative is not resized to its expected size, it stays at 1x1 and the ad is not visible.

Steps to reproduce

1. Create gpt managed OutOfPage ad slot
2. Setup prebid with an appropriate configuration and ad units i.e
   pbjs.addAdUnits({ code: 'GAM_AD_UNIT_CODE', mediaTypes: { banner: { sizes: [[300, 250], [300,600], [320,480], [336,280], [480,320]] } }, ortb2Imp: { instl:1 }, bids: [{ bidder: 'appnexus' ... }] })
3. Request bids, Prebid wins and prebid's universal creative is served (https://cdn.jsdelivr.net/npm/prebid-universal-creative@latest/dist/creative.js)

Expected results

Ad Iframe resized to match hb_size size

Actual results

Ad Iframe remains at 1x1 but contains width and height attributes with its expected values.
I.e. width=300 height=600

Other information

GPT Managed OutOfPage slots render the add inside a second iframe:

ad_slot_div [ id=ad_slot_id_0__container ]
--- Iframe1 [ id=google_ads_iframe_ad_unit_code_0 ]
------ Iframe2 [ id=ad_iframe ]
-------- Prebid Universal Creative code

[patmmccann]

seems to be a partial dupe of #interstitial

[danielguedesb]

Setting frameElement's style.width and style.height after this sets the correct size:

doc.defaultView.frameElement.style.width = width + 'px';
doc.defaultView.frameElement.style.height = height + 'px';

It doesn't seem to cause any issue / unwanted behaviour at first glance but I'm keen on hearing other opinions.
Thoughts?

[bretg]

It does look like this is a duplicate of #5917. Chris and I discussed and put a suggestion over there. Closing this. @danielguedesb - you can re-open if you disagree that it's a duplicate.