Implement CefBrowserHost::SetFocus for WinForms

[jankurianski]

In our app we need to programmatically set focus to the web browser, but we found it wasn't possible (Control.Focus() doesn't do it). This implements SetFocus so we could call SetFocus(true), which does work (input focus moves to the browser).

[amaitland]

Is it safe to new over the top of Focus?

[jankurianski]

It is a bit bad. I wasn't positive about this part of the change.

If someone has a ChromiumWebBrowser instance and calls Focus(), this implementation does get called and the browser gets focus. But if someone has a Control instance, it won't get called and the focus won't change.

So for example, if someone has a utility function like this that they pass a browser into as part of a list...

public void FocusLastControl(List<Control> controls)
{
    controls[controls.Count - 1].Focus();
}

... then it won't work (browser won't get focused).

I could just as easily leave this out so Focus() never works and doesn't give false hope to users, and they are forced to call SetFocus() which will always work. What do you think?

[amaitland]

I could just as easily leave this out so Focus() never works and doesn't give false hope to users, and they are forced to call SetFocus() which will always work. What do you think?

How about we leave that out for now, can discuss it further at a later date if required?

[amaitland]

Happy to merge otherwise 👍

[jankurianski]

The new Focus() method is now gone. A good call, cheers @amaitland 👍

[amaitland]

@jankurianski Thanks for the PR, much appreciated 👍