Missing binding of the `autocapitalize` attribute on the `<textarea>`

[fgirardey]

Description

The autocapitalize attribute binding is missing on the internal <textarea> element.

Expected outcome

For example with <iron-autogrow-textarea autocapitalize="characters"></iron-autogrow-textarea>

On an iPad the keyboard should be blocked on uppercase mode.

Actual outcome

On an iPad the keyboard isn't blocked on uppercase mode.

Live Demo

https://jsbin.com/buzukuc

Steps to reproduce

1. Put a paper-textearea or a iron-autogrow-textarea element in the page.
2. Set its capitalize attribute to characters.
3. Open the page on an iPad/Android or whatever with a virtual keyboard.
4. Type multiple characters on the input.

Browsers Affected

• [x] Chrome
• [x] Firefox
• [x] Safari 9
• [x] Safari 8
• [x] Safari 7
• [ ] Edge
• [ ] IE 11
• [ ] IE 10