Introduce a ToCssWithGuard trait

components/script/dom/cssconditionrule.rs

@@ -12,6 +12,7 @@ use dom::csssupportsrule::CSSSupportsRule;
 use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
+use style::shared_lock::SharedRwLock;
 use style::stylesheets::CssRules as StyleCssRules;
 
 #[dom_struct]
@@ -27,6 +28,9 @@ impl CSSConditionRule {
         }
     }
 
+    pub fn shared_lock(&self) -> &SharedRwLock {
+        self.cssgroupingrule.shared_lock()
+    }
 }
 
 impl CSSConditionRuleMethods for CSSConditionRule {

components/script/dom/cssfontfacerule.rs

@@ -12,8 +12,8 @@ use dom::window::Window;
 use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
+use style::shared_lock::ToCssWithGuard;
 use style::font_face::FontFaceRule;
-use style_traits::ToCss;
 
 #[dom_struct]
 pub struct CSSFontFaceRule {
@@ -47,6 +47,7 @@ impl SpecificCSSRule for CSSFontFaceRule {
     }
 
     fn get_css(&self) -> DOMString {
-        self.fontfacerule.read().to_css_string().into()
+        let guard = self.cssrule.shared_lock().read();
+        self.fontfacerule.read().to_css_string(&guard).into()
     }
 }

components/script/dom/cssgroupingrule.rs

@@ -14,6 +14,7 @@ use dom::cssstylesheet::CSSStyleSheet;
 use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
+use style::shared_lock::SharedRwLock;
 use style::stylesheets::CssRules as StyleCssRules;
 
 #[dom_struct]
@@ -40,6 +41,10 @@ impl CSSGroupingRule {
                                                   parent_stylesheet,
                                                   RulesSource::Rules(self.rules.clone())))
     }
+
+    pub fn shared_lock(&self) -> &SharedRwLock {
+        self.cssrule.shared_lock()
+    }
 }
 
 impl CSSGroupingRuleMethods for CSSGroupingRule {

components/script/dom/cssimportrule.rs

@@ -12,8 +12,8 @@ use dom::window::Window;
 use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
+use style::shared_lock::ToCssWithGuard;
 use style::stylesheets::ImportRule;
-use style_traits::ToCss;
 
 #[dom_struct]
 pub struct CSSImportRule {
@@ -49,6 +49,7 @@ impl SpecificCSSRule for CSSImportRule {
     }
 
     fn get_css(&self) -> DOMString {
-        self.import_rule.read().to_css_string().into()
+        let guard = self.cssrule.shared_lock().read();
+        self.import_rule.read().to_css_string(&guard).into()
     }
 }

components/script/dom/csskeyframesrule.rs

@@ -21,8 +21,8 @@ use servo_atoms::Atom;
 use std::sync::Arc;
 use style::keyframes::{Keyframe, KeyframeSelector};
 use style::parser::ParserContextExtraData;
+use style::shared_lock::ToCssWithGuard;
 use style::stylesheets::KeyframesRule;
-use style_traits::ToCss;
 
 #[dom_struct]
 pub struct CSSKeyframesRule {
@@ -134,7 +134,8 @@ impl SpecificCSSRule for CSSKeyframesRule {
     }
 
     fn get_css(&self) -> DOMString {
-        self.keyframesrule.read().to_css_string().into()
+        let guard = self.cssrule.shared_lock().read();
+        self.keyframesrule.read().to_css_string(&guard).into()
     }
 
     fn deparent_children(&self) {

components/script/dom/cssmediarule.rs

@@ -17,12 +17,13 @@ use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
 use style::media_queries::parse_media_query_list;
+use style::shared_lock::ToCssWithGuard;
 use style::stylesheets::MediaRule;
 use style_traits::ToCss;
 
 #[dom_struct]
 pub struct CSSMediaRule {
-    cssrule: CSSConditionRule,
+    cssconditionrule: CSSConditionRule,
     #[ignore_heap_size_of = "Arc"]
     mediarule: Arc<RwLock<MediaRule>>,
     medialist: MutNullableJS<MediaList>,
@@ -33,7 +34,7 @@ impl CSSMediaRule {
                      -> CSSMediaRule {
         let list = mediarule.read().rules.clone();
         CSSMediaRule {
-            cssrule: CSSConditionRule::new_inherited(parent_stylesheet, list),
+            cssconditionrule: CSSConditionRule::new_inherited(parent_stylesheet, list),
             mediarule: mediarule,
             medialist: MutNullableJS::new(None),
         }
@@ -76,7 +77,8 @@ impl SpecificCSSRule for CSSMediaRule {
     }
 
     fn get_css(&self) -> DOMString {
-        self.mediarule.read().to_css_string().into()
+        let guard = self.cssconditionrule.shared_lock().read();
+        self.mediarule.read().to_css_string(&guard).into()
     }
 }
 

components/script/dom/cssnamespacerule.rs

@@ -13,8 +13,8 @@ use dom::window::Window;
 use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
+use style::shared_lock::ToCssWithGuard;
 use style::stylesheets::NamespaceRule;
-use style_traits::ToCss;
 
 #[dom_struct]
 pub struct CSSNamespaceRule {
@@ -62,6 +62,7 @@ impl SpecificCSSRule for CSSNamespaceRule {
     }
 
     fn get_css(&self) -> DOMString {
-        self.namespacerule.read().to_css_string().into()
+        let guard = self.cssrule.shared_lock().read();
+        self.namespacerule.read().to_css_string(&guard).into()
     }
 }

components/script/dom/cssrule.rs

@@ -20,6 +20,7 @@ use dom::cssviewportrule::CSSViewportRule;
 use dom::window::Window;
 use dom_struct::dom_struct;
 use std::cell::Cell;
+use style::shared_lock::SharedRwLock;
 use style::stylesheets::CssRule as StyleCssRule;
 
 
@@ -103,6 +104,10 @@ impl CSSRule {
     pub fn parent_stylesheet(&self) -> &CSSStyleSheet {
         &self.parent_stylesheet
     }
+
+    pub fn shared_lock(&self) -> &SharedRwLock {
+        &self.parent_stylesheet.style_stylesheet().shared_lock
+    }
 }
 
 impl CSSRuleMethods for CSSRule {

components/script/dom/cssstylerule.rs

@@ -14,8 +14,8 @@ use dom::window::Window;
 use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
+use style::shared_lock::ToCssWithGuard;
 use style::stylesheets::StyleRule;
-use style_traits::ToCss;
 
 #[dom_struct]
 pub struct CSSStyleRule {
@@ -51,7 +51,8 @@ impl SpecificCSSRule for CSSStyleRule {
     }
 
     fn get_css(&self) -> DOMString {
-        self.stylerule.read().to_css_string().into()
+        let guard = self.cssrule.shared_lock().read();
+        self.stylerule.read().to_css_string(&guard).into()
     }
 }
 

components/script/dom/csssupportsrule.rs

@@ -16,13 +16,14 @@ use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
 use style::parser::ParserContext;
+use style::shared_lock::ToCssWithGuard;
 use style::stylesheets::SupportsRule;
 use style::supports::SupportsCondition;
 use style_traits::ToCss;
 
 #[dom_struct]
 pub struct CSSSupportsRule {
-    cssrule: CSSConditionRule,
+    cssconditionrule: CSSConditionRule,
     #[ignore_heap_size_of = "Arc"]
     supportsrule: Arc<RwLock<SupportsRule>>,
 }
@@ -32,7 +33,7 @@ impl CSSSupportsRule {
                      -> CSSSupportsRule {
         let list = supportsrule.read().rules.clone();
         CSSSupportsRule {
-            cssrule: CSSConditionRule::new_inherited(parent_stylesheet, list),
+            cssconditionrule: CSSConditionRule::new_inherited(parent_stylesheet, list),
             supportsrule: supportsrule,
         }
     }
@@ -75,6 +76,7 @@ impl SpecificCSSRule for CSSSupportsRule {
     }
 
     fn get_css(&self) -> DOMString {
-        self.supportsrule.read().to_css_string().into()
+        let guard = self.cssconditionrule.shared_lock().read();
+        self.supportsrule.read().to_css_string(&guard).into()
     }
 }

components/script/dom/cssviewportrule.rs

@@ -12,8 +12,8 @@ use dom::window::Window;
 use dom_struct::dom_struct;
 use parking_lot::RwLock;
 use std::sync::Arc;
+use style::shared_lock::ToCssWithGuard;
 use style::viewport::ViewportRule;
-use style_traits::ToCss;
 
 #[dom_struct]
 pub struct CSSViewportRule {
@@ -46,6 +46,7 @@ impl SpecificCSSRule for CSSViewportRule {
     }
 
     fn get_css(&self) -> DOMString {
-        self.viewportrule.read().to_css_string().into()
+        let guard = self.cssrule.shared_lock().read();
+        self.viewportrule.read().to_css_string(&guard).into()
     }
 }