From 5be81d04a77a96407d9c6fce534a6c0654cf96f3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Thu, 14 Sep 2017 20:55:45 +0200
Subject: [PATCH] style: Clear the UA cache on shutdown.
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MozReview-Commit-ID: KAGdhFb67hq
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
---
 components/style/stylist.rs | 9 +++++++++
 ports/geckolib/glue.rs      | 3 ++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/components/style/stylist.rs b/components/style/stylist.rs
index 8dcf9aace05..841b7483a8e 100644
--- a/components/style/stylist.rs
+++ b/components/style/stylist.rs
@@ -131,6 +131,10 @@ impl UserAgentCascadeDataCache {
     fn expire_unused(&mut self) {
         self.entries.retain(|e| !e.is_unique())
     }
+
+    fn clear(&mut self) {
+        self.entries.clear();
+    }
 }
 
 type PrecomputedPseudoElementDeclarations =
@@ -1502,6 +1506,11 @@ impl Stylist {
 
         // We may measure other fields in the future if DMD says it's worth it.
     }
+
+    /// Shutdown the static data that this module stores.
+    pub fn shutdown() {
+        UA_CASCADE_DATA_CACHE.lock().unwrap().clear()
+    }
 }
 
 /// This struct holds data which users of Stylist may want to extract
diff --git a/ports/geckolib/glue.rs b/ports/geckolib/glue.rs
index 452f373b0ff..46efbc51aef 100644
--- a/ports/geckolib/glue.rs
+++ b/ports/geckolib/glue.rs
@@ -130,7 +130,7 @@ use style::stylesheets::{StylesheetContents, SupportsRule};
 use style::stylesheets::StylesheetLoader as StyleStylesheetLoader;
 use style::stylesheets::keyframes_rule::{Keyframe, KeyframeSelector, KeyframesStepValue};
 use style::stylesheets::supports_rule::parse_condition_or_declaration;
-use style::stylist::RuleInclusion;
+use style::stylist::{RuleInclusion, Stylist};
 use style::thread_state;
 use style::timer::Timer;
 use style::traversal::DomTraversal;
@@ -186,6 +186,7 @@ pub extern "C" fn Servo_Shutdown() {
     // The dummy url will be released after shutdown, so clear the
     // reference to avoid use-after-free.
     unsafe { DUMMY_URL_DATA = ptr::null_mut(); }
+    Stylist::shutdown();
 }
 
 unsafe fn dummy_url_data() -> &'static RefPtr<URLExtraData> {