Select native-control font-size is too small

[acdvorak]

What MDC Web Version are you using?

0.34.1

What browser(s) is this bug affecting?

All (tested in Chrome 65)

What OS are you using?

macOS 10.13.3 (High Sierra)

What are the steps to reproduce the bug?

1. View the select demo page
2. View the select CodePen
3. Compare the font-size of the native <select> element

What is the expected behavior?

The <select class="mdc-select__native-control"> element should have a font-size of 16px.

What is the actual behavior?

The <select class="mdc-select__native-control"> element has a font-size of 11px.

Any other information you believe would be useful?

The select demo page uses Normalize.css, which sets select { font-size: 16px }.

When we switched to a native <select> element in #2462, we inadvertently relied on the font-size value from Normalize.

Instead, we should explicitly set font-size on .mdc-select__native-control in MDC.

[acdvorak]

It looks like there are a few more font-size inconsistencies:

• mdc-text-field__input vs. mdc-select__native-control
• mdc-select__label vs. mdc-floating-label

E.g.:

[acdvorak]

See #2527