style: Remove quite useless StyleChange constructor.

components/style/gecko/restyle_damage.rs

@@ -72,7 +72,8 @@ impl GeckoRestyleDamage {
         } else {
             StyleChange::Unchanged
         };
-        StyleDifference::new(GeckoRestyleDamage(nsChangeHint(hint)), change)
+        let damage = GeckoRestyleDamage(nsChangeHint(hint));
+        StyleDifference { damage, change }
     }
 
     /// Returns true if this restyle damage contains all the damage of |other|.

components/style/matching.rs

@@ -31,16 +31,6 @@ pub struct StyleDifference {
     pub change: StyleChange,
 }
 
-impl StyleDifference {
-    /// Creates a new `StyleDifference`.
-    pub fn new(damage: RestyleDamage, change: StyleChange) -> Self {
-        StyleDifference {
-            change: change,
-            damage: damage,
-        }
-    }
-}
-
 /// Represents whether or not the style of an element has changed.
 #[derive(Clone, Copy, Debug)]
 pub enum StyleChange {

components/style/servo/restyle_damage.rs

@@ -74,7 +74,7 @@ impl ServoRestyleDamage {
             // optimization to skip the cascade in those cases applies.
             StyleChange::Changed { reset_only: false }
         };
-        StyleDifference::new(damage, change)
+        StyleDifference { damage, change }
     }
 
     /// Returns a bitmask that represents a flow that needs to be rebuilt and