A11Y: SVG of notched-outline should have focusable="false" attribute for IE11

[mathiasschopmans]

What MDC Web Version are you using?

• Version: latest / 0.39.x
• Components: textfield with outline

What browser(s) is this bug affecting?

Internet Explorer 11

What OS are you using?

Windows 7 (modern.ie virtual box virtual machine)

What are the steps to reproduce the bug?

The bug can be reproduced, when viewing the docs with the mentioned browser.

• visit https://material-components.github.io/material-components-web-catalog/#/component/text-field
• click inside the first outlined textfield (Standard)
• press "tab"

What is the expected behavior?

• The SVG element shouldn't be focusable
• Focus should move to the next visible input-field (Dense)

What is the actual behavior?

• In IE11 the SVG will gain the focus therefore you need to
• press "tab" again to move the focus to the second element

Any other information you believe would be useful?

This can be fixed via the focusable="false" attribute:

<svg focusable="false">
    <path class="mdc-notched-outline__path" d=""/>
</svg>

If this issue will be accpeted, there README.mds of textfield and notched outline needs to be adapted and examples needs to be updated.

[kfranqueiro]

This will be resolved with #4035, because notched outline will no longer use SVG.

[mathiasschopmans]

Awesome news.