[REG 6.6 -> 6.7] WebOTP crashes renderer process

Opening web-otp.glitch.me in simplebrowser results in:

[150413:150413:0611/191011.807334:ERROR:render_process_host_impl.cc(5365)] Terminating render process for bad Mojo message: Received bad user message: No binder found for interface blink.mojom.WebOTPService for the frame/document scope
[150413:150413:0611/191011.807390:ERROR:bad_message.cc(29)] Terminating renderer for bad IPC message, reason 123

despite WebOTP being disabled by QtWebEngine.

From a related Brave browser issue:

The feature in Blink is not disabled when it's disabled in Chromium by default, because it has kSetOnlyIfOverridden option.

And indeed setting QTWEBENGINE_CHROMIUM_FLAGS=--disable-blink-features=WebOTP works around the crash.

From a quick look through src/3rdparty/chromium/content/child/runtime_features.cc, only WebOTP seems to have kSetOnlyIfOverridden set, other features logged as disabled by QtWebEngine seem to be fine:

* disable-features ConsolidatedMovementXY,InstalledApp,EyeDropper,BackgroundFetch,WebOTP,WebPayments,WebUSB).

Downstream issue: Crash on requesting one-time password on National Insurance website · Issue #8222 · qutebrowser/qutebrowser