There are also WPT and layout tests which depend on fullscreen being disallowed in same-origin frames without "allowfullscreen", which is being deprecated as well.

(That behaviour never really made any sense anyway, since a same-origin frame could always reach back into the parent and turn the attribute on if it wanted to.)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c3c6e3d369c0d2246d3e63eec0cddd12b7eaee2a

commit c3c6e3d369c0d2246d3e63eec0cddd12b7eaee2a
Author: iclelland <iclelland@chromium.org>
Date: Sat May 06 18:43:57 2017

Update tests for snapshot allowfullscreen behavior

As part of moving the Fullscreen API to Feature Policy, the behaviour of
the iframe "allowfullscreen" attribute is changing slightly -- it is now
being sampled once, when the frame content loads, and that value is used
when the frame tries to go fullscreen, regardless of whether it has been
changed. This CL updates the tests which were depending on that behavior
and introduces a new way of calling the cross-site-iframe-factory script
to attach additional attributes to iframes at creation time.

BUG= 718155 

Review-Url: https://codereview.chromium.org/2855973005
Cr-Commit-Position: refs/heads/master@{#469839}

[modify] https://crrev.com/c3c6e3d369c0d2246d3e63eec0cddd12b7eaee2a/chrome/browser/site_per_process_interactive_browsertest.cc
[modify] https://crrev.com/c3c6e3d369c0d2246d3e63eec0cddd12b7eaee2a/content/test/data/cross_site_iframe_factory.html
[modify] https://crrev.com/c3c6e3d369c0d2246d3e63eec0cddd12b7eaee2a/content/test/data/tree_parser_util.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5d8010e1fc081481d0646618e700b51a4699ab4c

commit 5d8010e1fc081481d0646618e700b51a4699ab4c
Author: iclelland <iclelland@chromium.org>
Date: Thu Aug 17 21:47:11 2017

Reenable feature policy control over fullscreen

This CL also changes test expectations to bring the fullscreen tests in
line with the new behaviour prescribed by Feature Policy.

Specifically:
 - Same origin iframes by default have the same ability to use
   fullscreen as their parent frame. Tests which previously only used
   same-origin frame have been changed to verify the new behaviour,
   and new tests in LayoutTests/http/tests have been added to test the
   same situation with cross-origin frames.
 - Dynamic modification of the allowfullscreen flag has no effect until
   the iframe contents are navigated/reloaded.
 - Web platform tests are marked as failing, and should remain so until
   the fullscreen spec is updated fo include the new behaviour.
 - A new Browser test class is created which explicitly disables
   feature policy so that we don't lose coverage for the old behaviour
   when FP is disabled.

BUG= 718155 , 623682 

Review-Url: https://codereview.chromium.org/2898503002
Cr-Commit-Position: refs/heads/master@{#495331}

[modify] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/content/browser/site_per_process_browsertest.cc
[modify] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/FlagExpectations/enable-blink-features=LayoutNG
[modify] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/TestExpectations
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/document-fullscreen-enabled-cross-origin.sub-expected.txt
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/document-fullscreen-enabled-cross-origin.sub.html
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/document-fullscreen-enabled-expected.txt
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/element-ready-check-allowed-cross-origin-manual.sub.html
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/element-ready-check-not-allowed-cross-origin-manual.sub.html
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/element-ready-check-not-allowed-manual-expected.txt
[rename] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/element-ready-check-not-allowed-manual.html
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/resources/attempt-fullscreen.html
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt/fullscreen/api/resources/report-fullscreen-enabled.html
[modify] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/external/wpt_automation/fullscreen/auto-click.js
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/fullscreen/full-screen-enabled-expected.txt
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/fullscreen/full-screen-enabled.html
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/fullscreen/full-screen-iframe-legacy-expected.txt
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/fullscreen/full-screen-iframe-legacy.html
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/http/tests/feature-policy/fullscreen-allowed-by-container-policy-expected.txt
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/http/tests/feature-policy/fullscreen-allowed-by-container-policy-relocate-expected.txt
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/http/tests/feature-policy/fullscreen-disabled-expected.txt
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/http/tests/feature-policy/fullscreen-enabledforall-expected.txt
[delete] https://crrev.com/81565fa69c0d5cdd4275fcf9d858f92b5e8aa551/third_party/WebKit/LayoutTests/http/tests/feature-policy/fullscreen-enabledforself-expected.txt
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/http/tests/fullscreen/resources/inner.html
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/http/tests/fullscreen/resources/legacy.html
[add] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/http/tests/fullscreen/resources/media-file.js
[modify] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/LayoutTests/resources/testharnessreport.js
[modify] https://crrev.com/5d8010e1fc081481d0646618e700b51a4699ab4c/third_party/WebKit/Source/platform/feature_policy/FeaturePolicy.cpp