Give intern::Interner an impl of Default.

webrender/src/intern.rs

@@ -204,9 +204,12 @@ pub struct Interner<S : Eq + Hash + Clone + Debug, D, M> {
     local_data: Vec<Item<D>>,
 }
 
-impl<S, D, M> Interner<S, D, M> where S: Eq + Hash + Clone + Debug, M: Copy + Debug {
-    /// Construct a new interner
-    pub fn new() -> Self {
+impl<S, D, M> ::std::default::Default for Interner<S, D, M>
+where
+    S: Eq + Hash + Clone + Debug,
+    M: Copy + Debug
+{
+    fn default() -> Self {
         Interner {
             map: FastHashMap::default(),
             free_list: Vec::new(),
@@ -217,7 +220,9 @@ impl<S, D, M> Interner<S, D, M> where S: Eq + Hash + Clone + Debug, M: Copy + De
             local_data: Vec::new(),
         }
     }
+}
 
+impl<S, D, M> Interner<S, D, M> where S: Eq + Hash + Clone + Debug, M: Copy + Debug {
     /// Intern a data structure, and return a handle to
     /// that data. The handle can then be stored in the
     /// frame builder, and safely accessed via the data

webrender/src/scene_builder.rs

@@ -159,20 +159,12 @@ pub enum SceneSwapResult {
 //   display lists is (a) fast (b) done during scene building.
 #[cfg_attr(feature = "capture", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]
+#[derive(Default)]
 pub struct DocumentResources {
     pub clip_interner: ClipDataInterner,
     pub prim_interner: PrimitiveDataInterner,
 }
 
-impl DocumentResources {
-    fn new() -> Self {
-        DocumentResources {
-            clip_interner: ClipDataInterner::new(),
-            prim_interner: PrimitiveDataInterner::new(),
-        }
-    }
-}
-
 // A document in the scene builder contains the current scene,
 // as well as a persistent clip interner. This allows clips
 // to be de-duplicated, and persisted in the GPU cache between
@@ -187,7 +179,7 @@ impl Document {
     fn new(scene: Scene) -> Self {
         Document {
             scene,
-            resources: DocumentResources::new(),
+            resources: DocumentResources::default(),
             prim_store_stats: PrimitiveStoreStats::empty(),
         }
     }