Make Fast Fetch the only means of requesting/rendering ads on AMP Pages using DoubleClick <amp-ad> tags. Fully deprecate the Delayed Fetch request/rendering path for DoubleClick <amp-ad> tags.

Background

AMP pages originally used Delayed Fetch for all ad requests, in which a standard ad tag (e.g. GPT or GPT Light for DoubleClick) would be loaded inside of a cross-domain iframe in the AMP page. Fast Fetch, conversely, is the AMP-specific implementation of an ad tag, in which the ad tag's code is its own AMP extension. There are still several remaining steps needed to deprecate Delayed Fetch, as outlined below.

Requirements

Deprecate Remote.html

Remote.html is a feature of Delayed Fetch in which a publisher can specify the src for the cross-domain iframe in which the ad tag loads, as a way to allow the publisher to add first-party targeting information to the ad request. Currently, specifying remote.html causes a page to be invalid for Doubleclick Fast Fetch and thus uses Delayed Fetch. However, with the introduction of Real Time Config (RTC) as part of Fast Fetch, publishers can now add per-user targeting to ad requests in Fast Fetch. Thus, the presence of remote.html will be ignored entirely.

Required steps:

1. Add warning logged to console on pages with DoubleClick tags using remote.html that it will be deprecated by March 29, 2018, with link to docs on how to transition to RTC.
2. Remove carve out for remote.html by March 29, 2018.

Add SafeFrame API

Currently, publishers have the option of using the flag useSameDomainRenderingUntilDeprecated on their DoubleClick tags, which forces out of using Fast Fetch. This flag was originally created as a carve out for Delayed Fetch, which would cause the regular GPT tag to be used instead of GPT Light (glade.js). This was due to the issue where creatives rendered via GPT Light were not rendered within the same frame as the tag, which meant that creatives could not access window.context, which contained useful APIs. This flag also forces out of Fast Fetch because creatives also do not have access to those same APIs if rendered via Fast Fetch. Going forward, creatives should use the Safeframe API, which in addition to replacing functionality from window.context, allows the creatives to no longer need to write code specific to the AMP environment.

Required steps:

1. Add warning logged to console on pages using the useSameDomainRenderingUntilDeprecated that the flag will be deprecated by March 29, 2018.
2. Implement SafeFrame API for nested iframes in Fast Fetch
3. Remove support for useSameDomainRenderingUntilDeprecated by March 29, 2018

Canonical AMP Fast Fetch

Fast Fetch has so far only been allowed on pages loaded from the AMP CDN. Moving forward, Fast Fetch for DoubleClick will be allowed on any AMP page, regardless of its source. There are no required steps for publishers, which makes this the most straightforward change. There is already an ongoing experiment for adding this functionality, which will be launched soon.