From 950451a844d3830180c250895c0b841e07af7652 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Sat, 17 Dec 2016 14:40:33 -0800
Subject: [PATCH] servo: Merge #14622 - stylo: Track the last restyle
 generation properly (from emilio:last-restyle); r=bholley

I couldn't reproduce locally, but I believe this fixes:

https://bugzilla.mozilla.org/show_bug.cgi?id=1323890

r? @heycam

Source-Repo: https://github.com/servo/servo
Source-Revision: f6163c77b9ac979f8406ef6ffe90e8c8e4a054cc
---
 servo/components/style/gecko/data.rs | 10 ++++++++++
 servo/ports/geckolib/glue.rs         |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/servo/components/style/gecko/data.rs b/servo/components/style/gecko/data.rs
index da334bfa4bf4..2b7cfc54a35a 100644
--- a/servo/components/style/gecko/data.rs
+++ b/servo/components/style/gecko/data.rs
@@ -25,6 +25,9 @@ pub struct PerDocumentStyleDataImpl {
     /// Rule processor.
     pub stylist: Arc<Stylist>,
 
+    /// Last restyle generation.
+    pub last_restyle_generation: u32,
+
     /// List of stylesheets, mirrored from Gecko.
     pub stylesheets: Vec<Arc<Stylesheet>>,
 
@@ -64,6 +67,7 @@ impl PerDocumentStyleData {
 
         PerDocumentStyleData(AtomicRefCell::new(PerDocumentStyleDataImpl {
             stylist: Arc::new(Stylist::new(device)),
+            last_restyle_generation: 0,
             stylesheets: vec![],
             stylesheets_changed: true,
             new_animations_sender: new_anims_sender,
@@ -101,6 +105,12 @@ impl PerDocumentStyleDataImpl {
             self.stylesheets_changed = false;
         }
     }
+
+    pub fn next_generation(&mut self) -> u32 {
+        self.last_restyle_generation =
+            self.last_restyle_generation.wrapping_add(1);
+        self.last_restyle_generation
+    }
 }
 
 unsafe impl HasFFI for PerDocumentStyleData {
diff --git a/servo/ports/geckolib/glue.rs b/servo/ports/geckolib/glue.rs
index 3194001b4509..4b20c76f0b25 100644
--- a/servo/ports/geckolib/glue.rs
+++ b/servo/ports/geckolib/glue.rs
@@ -106,7 +106,7 @@ fn create_shared_context(mut per_doc_data: &mut AtomicRefMut<PerDocumentStyleDat
         // FIXME (bug 1303229): Use the actual viewport size here
         viewport_size: Size2D::new(Au(0), Au(0)),
         screen_size_changed: false,
-        generation: 0,
+        generation: per_doc_data.next_generation(),
         goal: ReflowGoal::ForScriptQuery,
         stylist: per_doc_data.stylist.clone(),
         running_animations: per_doc_data.running_animations.clone(),