Invalid font CSS for mat-input-container class

[robmv]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

font CSS style for .mat-input-container should be valid

What is the current behavior?

Default typography theme set

font: 400 inherit/1.125 Roboto,Helvetica Neue,sans-serif

which both Firefox and Chrome developer tools show as invalid (the inherit value for font-size). So all Input fields are not correctly font styled, only if a parent is (for example body).

What are the steps to reproduce?

Check https://material.angular.io/components/input/examples and go to the inspector and notice the invalid CSS

What is the use-case or motivation for changing an existing behavior?

To have correct default Roboto fonts styles on input field without depending on body styles like beta 6 did

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Material beta 7

Is there anything else we should know?

[crisbeto]

Will be fixed by #5154.