[CSS Shapes] Optimize relayout when shape-outside changes

• Component: CSS
• Status: RESOLVED CONFIGURATION CHANGED

[Bear Travis]

The layout code can repeatedly remove a float from the block lists, which is costly. This should be consolidated or short circuited so the heavy lifting is only done once.
See RenderElement::styleWillChange, RenderBox::styleWillChange, and RenderBox::styleDidChange.

Also, are there cases where removing / adding / changing a shape would not require relayout, and should we optimize for these?

[Brent Fulgham]

This code has been significantly refactored since this improvement was proposed. There doesn't seem to be any action we can take here.