The `flex` properties can not be set

[nightskylark]

Hello.
I have found a bug. The flex property keeps being undefined after the 'flex-*` properties are set.
I was redirected here from the Angular Universal repository. Please see this issue to get more details:
angular/universal#935

UPD: I have found that the problem is deeper. It is impossible to set any flex property for an element.
They do not appear in the style attribute of an element.

element.style.flex = '1 1 0px';
// element.style.flex is undefined
element.style.flexBase = '0px';
// element.style.flexBase is undefined
element.style.flexGrow = 1;
// element.style.flexGrow is undefined
element.style.flexShrink = 1;
// element.style.flexShrink is undefined