Bug 315664 – [Site Isolation] iframe monitor tests are failing

• Component: WebKit Process Model
• Status: RESOLVED FIXED

[Anthony Tarbinian]

The following tests are failing with site isolation:

http/tests/iframe-monitor/eligibility.html
http/tests/iframe-monitor/iframe-unload.html
http/tests/iframe-monitor/throttler.html
http/tests/iframe-monitor/workers/service-worker-not-count-twice.html
http/tests/iframe-monitor/workers/service-worker.html
http/tests/iframe-monitor/workers/shared-worker.html

Note that this doesn't cover http/tests/iframe-memory-monitor/media-video-autoplay-in-frames.html

These 6 tests in http/tests/iframe-monitor/ timed out under 
--site-isolation. The tests use a WebKit feature
which enforces a resource usage threshold for iframes. When an 
iframe goes over the resource usage threshold, the iframe is killed
by getting swapped out with a gray placeholder iframe that reads: 
"this frame is hidden".

The first bug was that WebLocalFrameLoaderClient::didExceedNetworkUsageThreshold
assumes that the main frame is a local frame. This isn't true with
site isolation. It uses the local main frame to grab the URL of the
main frame and send it via the Messages::NetworkConnectionToWebProcess::ShouldOffloadIFrameForHost
IPC message.

With site isolation enabled, the main frame's document wasn't available
and didExceedNetworkUsageThreshold returned early, never sending the
NetworkConnectionToWebProcess::ShouldOffloadIFrameForHost IPC message.

The second bug was that LocalFrame::showResourceMonitoringError
tried to use ownerElement() to set the srcdoc of the iframe.
With site isolation enabled, the owner element was in a different process
and was nullptr.

The third bug, involves settings on internals.* to not be propagated 
to all processes which is problematic for site isolation.

[Radar WebKit Bug Importer]

<rdar://problem/178052024>

[Anthony Tarbinian]

Pull request: https://github.com/WebKit/WebKit/pull/65806

[EWS]

Committed 314057@main (270a9fa5f162): <https://commits.webkit.org/314057@main>

Reviewed commits have been landed. Closing PR #65806 and removing active labels.