Intent to implement: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/e7I1tZAfavU

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c215868e0e24be1d8498c93ce7b8db20cb202fed

commit c215868e0e24be1d8498c93ce7b8db20cb202fed
Author: Becca Hughes <beccahughes@chromium.org>
Date: Fri Sep 22 11:25:19 2017

Activation Delegation: Add feature flag to implement.

Add a feature flag "AllowActivationDelegationAttr" to enable the
"allowActivationDelegation" attribute on <iframe>.

BUG= 766090 

Change-Id: I75cc542348fbd72ee73ab212ea31d53ad987abd6
Reviewed-on: https://chromium-review.googlesource.com/678720
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#503711}
[modify] https://crrev.com/c215868e0e24be1d8498c93ce7b8db20cb202fed/content/child/runtime_features.cc
[modify] https://crrev.com/c215868e0e24be1d8498c93ce7b8db20cb202fed/content/public/common/content_features.cc
[modify] https://crrev.com/c215868e0e24be1d8498c93ce7b8db20cb202fed/content/public/common/content_features.h
[modify] https://crrev.com/c215868e0e24be1d8498c93ce7b8db20cb202fed/third_party/WebKit/Source/platform/exported/WebRuntimeFeatures.cpp
[modify] https://crrev.com/c215868e0e24be1d8498c93ce7b8db20cb202fed/third_party/WebKit/Source/platform/runtime_enabled_features.json5
[modify] https://crrev.com/c215868e0e24be1d8498c93ce7b8db20cb202fed/third_party/WebKit/public/platform/WebRuntimeFeatures.h

Is this any closer? The January deadline for Chrome Autoplay changes is approaching and we're eager to test this on our app.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/89450131a88528c94d28f642b3335f2925cf0cb4

commit 89450131a88528c94d28f642b3335f2925cf0cb4
Author: Becca Hughes <beccahughes@chromium.org>
Date: Thu Oct 26 15:14:25 2017

Activation Delegation: Add web platform tests

Add web platform tests for the delegateStickyUserActivation attr. The
tests are expected to fail for now since the attribute code has not
landed.

BUG= 766090 

Change-Id: Ieadc9c57b91bbe7ae78ba3e29c17fdf2efd09997
Reviewed-on: https://chromium-review.googlesource.com/735485
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#511821}
[modify] https://crrev.com/89450131a88528c94d28f642b3335f2925cf0cb4/third_party/WebKit/LayoutTests/external/wpt/html/dom/elements-embedded.js
[modify] https://crrev.com/89450131a88528c94d28f642b3335f2925cf0cb4/third_party/WebKit/LayoutTests/external/wpt/html/dom/interfaces-expected.txt
[modify] https://crrev.com/89450131a88528c94d28f642b3335f2925cf0cb4/third_party/WebKit/LayoutTests/external/wpt/html/dom/reflection-embedded-expected.txt
[modify] https://crrev.com/89450131a88528c94d28f642b3335f2925cf0cb4/third_party/WebKit/LayoutTests/external/wpt/interfaces/html.idl

Has there been any movement on this, or updates? According to this thread it looks as though this may no longer be in development/planned: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/F4h7sdBdiBM

We are moving to use the feature policy API instead. Please see  crbug.com/788390