CL -> https://chromium-review.googlesource.com/828002

Note regarding contrast for the blue/prominent buttons:

White on kGoogleBlue500 is a contrast ratio of 3.6, which is less than the 4.5 requirement from WCAG (https://www.w3.org/TR/WCAG20-TECHS/G18.html).

 - http://leaverou.github.io/contrast-ratio/#white-on-rgb%2866%2C%20133%2C%20244%29

WCAG defines lower thresholds for bold text, which will no longer apply to this after removing bold.

But solid white on kGoogleBlue500 has an exception granted - see http://go/mdcontrast

Removing the bold from the non-default buttons seems to have a bigger than expected impact too.
The contrast ratio is only just below the requirement, at 4.4: 
http://leaverou.github.io/contrast-ratio/#rgb%28120%2C%20120%2C%20120%29-on-white

But since the font doesn't occupy many pixels, most of them get a font that is lighter than #787878

Also the result when that LCD font-smoothing checkbox is unchecked is awful.

I don't think we can land that CL.

Deleted: nobold.png 33.2 KB

	nobold.png 33.2 KB View Download

actually those two screengrabs are with a bold font. (and the one without font smoothing still looks bad)

Deleted: largefont_bold.png 83.7 KB

	largefont_bold.png 83.7 KB View Download

Deleted: nofontsmoothing_boldtext.png 23.4 KB

	nofontsmoothing_boldtext.png 23.4 KB View Download

MacViews triage: this reproduces for me. Assigning to spqchan@ for M-69 fix.

Note I'm not sure what action should be taken here. I think we are still happy with how things are shipping, but might want a mac-specific tweak once things settle down. It might involve detecting the `font smoothing` setting and acting on that as well as (how we do currently) on macOS-version.

Fixing the bug as written will make the button font too scratchy (and low-contrast) for users without font-smoothing enabled.

macviews triage: lgrey@, over to you :)

bettes@ what's your take on c#5?

bettes: Making it NORMAL for all macOS versions lgtm.

Note that macOS 10.14 Mojave has dropped support for subpixel AA, so the premise that "the system font renders kinda bold-looking" will no longer hold true there. (i.e. since filing this bug, this new info suggests that we may actually want MEDIUM again).