Wrong snack-bar width

[LastDragon-ru]

What is the expected behavior?

Valid snack-bar width.

What is the current behavior?

Snack-bar's width depends from window's height :) (this is because snack-bar uses Breakpoints.Handset, seems Breakpoints.XSmall is more suitable in this case?)

What are the steps to reproduce?

1. Go to https://material.angular.io/components/snack-bar/examples
2. Set windows size like on gif
3. Press on Pizza

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

Desktop, Chrome/Firefox, Material: 7.3.7

[jonathanRinciari]

@jelbourn Would like some feedback on the spec. Taking a look it appears that this might be valid to accommodate landscape on mobile/small screen. My take on the spec is that small screen should have a full width to allow for a maximum of 2 lines of text. I have made a PR to address this issue though.