[Problem/Bug]: Enabling AllowHostInputProcessing breaks Gamepad API

[AshleyScirra]

What happened?

As of WebView2 SDK v1.0.3351.48, AllowHostInputProcessing can be enabled to allow the app process window to handle input. We enabled this as it's important for our purposes (in this case, Steam integration with Construct). However when enabled, the Gamepad API entirely stops working for web content. The documentation does not mention anything about AllowHostInputProcessing affecting gamepad input - only mouse, keyboard, touch etc. - and by default enabling that option does not affect input to the web content, so this appears to be a bug. As Construct is game development software and people often want to play games with gamepads, this is a blocking issue for us.

Importance

Blocking. My app's basic functions are not working due to this issue.

Runtime Channel

Stable release (WebView2 Runtime)

Runtime Version

141.0.3537.99

SDK Version

v1.0.3351.48 and newer

Framework

Win32

Operating System

Windows 11

OS Version

26200.6901

Repro steps

Minimal repro: WebView2GamepadIssue.zip

This is just the Win32_GettingStarted sample updated for the latest SDK, loading this gamepad tester, and with the minimum necessary additions to call controllerOpts4->put_AllowHostInputProcessing(TRUE);. Changing that to FALSE gets gamepad input working again.

Repros in Edge Browser

No, issue does not reproduce in the corresponding Edge version

Regression

No, this never worked

Last working version (if regression)

No response