Auto merge of #13202 - emilio:rule-tree, r=SimonSapin,Manishearth,emilio

Rule tree, v1

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors

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- [x] There are tests for these changes OR

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This patch introduces infrastructure for the rule tree, and constructs it.

We don't use it yet, nor have good heuristics for GC'ing it, but this should not
happen anymore once we store the rule node reference in the node.

I haven't messed up with memory orders because I want to do a try run with it,
then mess with them.

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1 files changed, 4 insertions, 2 deletions

diff --git a/components/style/parallel.rs b/components/style/parallel.rs
index 8c30868224d..6740c4f379c 100644
--- a/components/style/parallel.rs
+++ b/components/style/parallel.rs
@@ -33,7 +33,8 @@ pub fn run_queue_with_custom_work_data_type<To, F, SharedContext: Sync>(
         queue: &mut WorkQueue<SharedContext, WorkQueueData>,
         callback: F,
         shared: &SharedContext)
-        where To: 'static + Send, F: FnOnce(&mut WorkQueue<SharedContext, To>) {
+    where To: 'static + Send, F: FnOnce(&mut WorkQueue<SharedContext, To>)
+{
     let queue: &mut WorkQueue<SharedContext, To> = unsafe {
         mem::transmute(queue)
     };
@@ -73,7 +74,8 @@ pub fn traverse_dom<N, C>(root: N,
 #[inline(always)]
 fn top_down_dom<N, C>(unsafe_nodes: UnsafeNodeList,
                       proxy: &mut WorkerProxy<C::SharedContext, UnsafeNodeList>)
-                      where N: TNode, C: DomTraversalContext<N> {
+    where N: TNode, C: DomTraversalContext<N>
+{
     let context = C::new(proxy.user_data(), unsafe_nodes.1);
 
     let mut discovered_child_nodes = vec![];