layout: Dump damage as well as part of the flow tree debug spew.

components/layout/flow.rs

@@ -940,11 +940,12 @@ pub struct BaseFlow {
 impl fmt::Debug for BaseFlow {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f,
-               "@ {:?}, CC {}, ADC {}, Ovr {:?}",
+               "@ {:?}, CC {}, ADC {}, Ovr {:?}, Dmg {:?}",
                self.position,
                self.parallel.children_count.load(Ordering::SeqCst),
                self.abs_descendants.len(),
-               self.overflow)
+               self.overflow,
+               self.restyle_damage)
     }
 }