[Bug 27658] Create algorithm for "for element that;s bigger then the viewport. we scroll to 0,0 of that element. If the element can not be fully scrolled take a screenshot of the element that is in the viewport" for takesElementScreenshot
[Bug 27663] specify that interpretation of required capabilities depends on the capability itself; whether it's met or not. Language for that each one is special cased. What it means to fulfil a capability is defined by that capability itself