SmoothScroll breaks text input inside web components

[brettflorio]

This extension prevents certain text input (like the spacebar) inside web components. Instead of entering a space, the page will scroll. This behavior can be seen here:

• The search input here: http://www.twelvetone.tv/iron-icons-search/index.html (search "icon" so there's plenty to actually scroll).
• The email input here: https://vaadin.com/components/vaadin-email-field/html-examples/email-field-demos
• Combo box text input: https://vaadin.com/components/vaadin-combo-box/html-examples
• Any other text input inside a web component.

The extension should ignore text input when a web component (any element with a - in the node name) is focused.