It would be nice to have a way to visualize backing store and screen updates in WebKit2. Something similar to Quartz Debug's "Flash screen updates" would work well.
I have a patch, but it only gets this feature working on Windows. Other platforms will have to implement PageClient::flashBackingStoreUpdates, and flash their views' updates at the appropriate time.
Created attachment 82325 [details] Add a way to flash backing store and view updates
Committed r78488: <http://trac.webkit.org/changeset/78488>