From b9a0737946f809444037f8dc168508bf24bba889 Mon Sep 17 00:00:00 2001
From: Boris Zbarsky <bzbarsky@mit.edu>
Date: Thu, 18 May 2017 11:32:49 -0400
Subject: [PATCH] Use snapshot class/id flags to optimize out class/id gets.

---
 components/style/gecko/snapshot.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/components/style/gecko/snapshot.rs b/components/style/gecko/snapshot.rs
index ea4871bc2a7..261af44f6d6 100644
--- a/components/style/gecko/snapshot.rs
+++ b/components/style/gecko/snapshot.rs
@@ -148,7 +148,12 @@ impl ElementSnapshot for GeckoElementSnapshot {
         self.has_any(Flags::Attributes)
     }
 
+    #[inline]
     fn id_attr(&self) -> Option<Atom> {
+        if !self.has_any(Flags::Id) {
+            return None
+        }
+
         let ptr = unsafe {
             bindings::Gecko_SnapshotAtomAttrValue(self,
                                                   atom!("id").as_ptr())
@@ -161,15 +166,25 @@ impl ElementSnapshot for GeckoElementSnapshot {
         }
     }
 
+    #[inline]
     fn has_class(&self, name: &Atom) -> bool {
+        if !self.has_any(Flags::MaybeClass) {
+            return false;
+        }
+
         snapshot_helpers::has_class(self.as_ptr(),
                                     name,
                                     bindings::Gecko_SnapshotClassOrClassList)
     }
 
+    #[inline]
     fn each_class<F>(&self, callback: F)
         where F: FnMut(&Atom)
     {
+        if !self.has_any(Flags::MaybeClass) {
+            return;
+        }
+
         snapshot_helpers::each_class(self.as_ptr(),
                                      callback,
                                      bindings::Gecko_SnapshotClassOrClassList)