We see when profiling on embedded during app startup and when adding a new content for example going to a new application page. I large amount of time is spent applying CSS the first time to UI Controls. The idea here is if controls are using the default theme then we already know what properties will be applied and what cached state we will need. Is there a way that we can pre apply this in code by setting property defaults etc then setting the relevant flags as clean so we don't have to apply CSS to a control if its just default theme in default state.

Related idea to RT-29866