From 8d7a3683771f79c6ebaabc2d526ef387fbbae1a1 Mon Sep 17 00:00:00 2001
From: Manish Goregaokar <manishsmail@gmail.com>
Date: Tue, 18 Jul 2017 12:40:01 -0700
Subject: [PATCH] stylo: Don't ignore visited state when deciding to share
 style contexts

---
 components/style/sharing/checks.rs | 15 ---------------
 components/style/sharing/mod.rs    |  5 ++++-
 2 files changed, 4 insertions(+), 16 deletions(-)

diff --git a/components/style/sharing/checks.rs b/components/style/sharing/checks.rs
index b710dffdc4d..8ff232d7f42 100644
--- a/components/style/sharing/checks.rs
+++ b/components/style/sharing/checks.rs
@@ -10,7 +10,6 @@ use Atom;
 use bloom::StyleBloom;
 use context::{SelectorFlagsMap, SharedStyleContext};
 use dom::TElement;
-use element_state::*;
 use sharing::{StyleSharingCandidate, StyleSharingTarget};
 use stylearc::Arc;
 
@@ -68,20 +67,6 @@ pub fn have_same_class<E>(target: &mut StyleSharingTarget<E>,
     target.class_list() == candidate.class_list()
 }
 
-/// Compare element and candidate state, but ignore visitedness.  Styles don't
-/// actually changed based on visitedness (since both possibilities are computed
-/// up front), so it's safe to share styles if visitedness differs.
-pub fn have_same_state_ignoring_visitedness<E>(element: E,
-                                               candidate: &StyleSharingCandidate<E>)
-                                               -> bool
-    where E: TElement,
-{
-    let state_mask = !IN_VISITED_OR_UNVISITED_STATE;
-    let state = element.get_state() & state_mask;
-    let candidate_state = candidate.element.get_state() & state_mask;
-    state == candidate_state
-}
-
 /// Whether a given element and a candidate match the same set of "revalidation"
 /// selectors.
 ///
diff --git a/components/style/sharing/mod.rs b/components/style/sharing/mod.rs
index 462d0b16e1e..daf81862c38 100644
--- a/components/style/sharing/mod.rs
+++ b/components/style/sharing/mod.rs
@@ -643,7 +643,10 @@ impl<E: TElement> StyleSharingCandidateCache<E> {
             miss!(UserAndAuthorRules)
         }
 
-        if !checks::have_same_state_ignoring_visitedness(target.element, candidate) {
+        // We do not ignore visited state here, because Gecko
+        // needs to store extra bits on visited style contexts,
+        // so these contexts cannot be shared
+        if target.element.get_state() != candidate.get_state() {
             miss!(State)
         }