tle>App name</div>
  <paper-icon-button icon="search"></paper-icon-button>
</app-toolbar>
```

You can use the attributes `top-item` or `bottom-item` to completely fit an element
to the top or bottom of the toolbar respectively.

### Content attributes

Attribute            | Description
---------------------|---------------------------------------------------------
`main-title`         | The main title element.
`condensed-title`    | The title element if used inside a condensed app-header.
`spacer`        