Remove MDL2 from code

[Jay-o-Way]

Description

Let's not use MDL2 :)

Motivation and Context

Closes: #1252

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

[tashatitova]

We can't just remove it like that. We use SymbolThemeFontFamily that redirects to appropriate font for controls that use icons. Otherwise it will fall back to Xaml Auto Font Family which is a text font. Also, all these instances would need to be tested, for example, AnimatedIcon

[Jay-o-Way]

@tashatitova that's highly peculiar because this very app shows examples just like this. <Fonticon glyph="">

Also (as mentioned in the issue) it renders just fine.

Can you show how it looks? Need some convincing here.

[tashatitova]

FontIcon defaults to SymbolThemeFontFamily, but usage without setting the FontFamily isn't something recommended, at least as far as I've seen. Textblocks do come without font sent on them, FontIcons usually specify it.

[Jay-o-Way]

Can you show how it looks on your device?

[Jay-o-Way]

@tashatitova

FontIcon defaults to SymbolThemeFontFamily

This speaks for itself. It's 100% redundant.

If you don't specify a FontFamily, or you specify a FontFamily that is not available on the system at runtime, the FontIcon falls back to the default font family defined by the SymbolThemeFontFamily theme resource.

By default, Windows uses the Segoe Fluent Icon font family. If your app is run on Windows 10, version 20H2 or earlier, the Segoe Fluent Icon font family is not available and the SymbolThemeFontFamily resource falls back to the Segoe MDL2 Asset font family instead. To use glyphs from the default system font, don't set the FontFamily property, let it use its default value.

https://learn.microsoft.com/windows/windows-app-sdk/api/winrt/microsoft.ui.xaml.controls.fonticon?view=windows-app-sdk-1.2#default-font-family

isn't something recommended, at least as far as I've seen

Have a look at WinUI 3 Gallery, it's a good source:

<DropDownButton AutomationProperties.Name="Email">
    <DropDownButton.Content>
        <FontIcon Glyph="&#xE715;"/>
    </DropDownButton.Content>
    <DropDownButton.Flyout>
        <MenuFlyout Placement="Bottom">
            <MenuFlyoutItem Text="Send">
                <MenuFlyoutItem.Icon>
                    <FontIcon Glyph="&#xE725;"/>
                </MenuFlyoutItem.Icon>
            </MenuFlyoutItem>
            <MenuFlyoutItem Text="Reply">
                <MenuFlyoutItem.Icon>
                    <FontIcon Glyph="&#xE8CA;"/>
                </MenuFlyoutItem.Icon>

[Jay-o-Way]

@niels9001 I'm ready

[niels9001]

Thanks, changes look good.

FontIcon falls back automatically to SymbolThemeFontFamily