Stop using associated types for the concrete TRestyleDamage implementation.

MozReview-Commit-ID: LfaZFCVlIb1

components/style/gecko/restyle_damage.rs

@@ -0,0 +1,53 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use dom::TRestyleDamage;
+use gecko_bindings::bindings;
+use gecko_bindings::structs::{nsChangeHint, nsStyleContext};
+use gecko_bindings::sugar::ownership::FFIArcHelpers;
+use properties::ComputedValues;
+use std::ops::BitOr;
+use std::sync::Arc;
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct GeckoRestyleDamage(nsChangeHint);
+
+impl GeckoRestyleDamage {
+    pub fn as_change_hint(&self) -> nsChangeHint {
+        self.0
+    }
+}
+
+impl TRestyleDamage for GeckoRestyleDamage {
+    type PreExistingComputedValues = nsStyleContext;
+
+    fn empty() -> Self {
+        use std::mem;
+        GeckoRestyleDamage(unsafe { mem::transmute(0u32) })
+    }
+
+    fn compute(source: &nsStyleContext,
+               new_style: &Arc<ComputedValues>) -> Self {
+        let context = source as *const nsStyleContext as *mut nsStyleContext;
+        let hint = unsafe {
+            bindings::Gecko_CalcStyleDifference(context,
+                                                new_style.as_borrowed_opt().unwrap())
+        };
+        GeckoRestyleDamage(hint)
+    }
+
+    fn rebuild_and_reflow() -> Self {
+        GeckoRestyleDamage(nsChangeHint::nsChangeHint_ReconstructFrame)
+    }
+}
+
+impl BitOr for GeckoRestyleDamage {
+    type Output = Self;
+
+    fn bitor(self, other: Self) -> Self {
+        use std::mem;
+        GeckoRestyleDamage(unsafe { mem::transmute(self.0 as u32 | other.0 as u32) })
+    }
+}
+