Summary:
Currently, our configuration of Views looks like this:
```objc
UIView *view = [[UIView alloc] initWithFrame:CGRectZero];
view.yoga.isEnabled = YES;
view.yoga.height = 50;
view.yoga.width = 50;
```
Every time that we access `view.yoga` we have to access the associated object on `UIView` to get the `YGLayout`. This adds an extra `objc_msgSend` which increases binary size, and is slight perf impact.
This diff creates a way to modify the `YGLayout` with only a single `objc_msgSend`. Here's the new syntax:
```objc
UIView *view = [[UIView alloc] initWithFrame:CGRectZero];
[view configureLayoutWithBlock:^void(YGLayout *layout){
layout.isEnabled = YES
layout.height = 50;
layout.width = 50;
}];
```
Here's the Swift version:
```swift
let view = UIView(frame: .zero)
view.configureLayout { (layout) in
layout.isEnabled = true
layout.height = 50
layout.width = 50
}
```
Closes https://github.com/facebook/yoga/pull/393
Reviewed By: emilsjolander
Differential Revision: D4550382
Pulled By: dshahidehpour
fbshipit-source-id: 76d797d1e0de8e5dc767e02180a7fc440a70212e
ae9f89b5d1