Auto merge of #14646 - canaltinova:origin-clean, r=jdm

Support origins in CSSOM stylesheets

<!-- Please describe your changes on the following line: -->
I still need to pass the origin clean flag to constructors. `style::stylesheets::Stylesheet` has an origin field but I don't think that's relevant.
I can get href in htmllinkelement.rs like this:
```rust
let element = self.upcast::<Element>();
let href = element.get_string_attribute(&local_name!("href"));
```
But I'm not sure how to proceed after here.
@Manishearth any opinions?

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #14327 (github issue number if applicable).

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- [X] There are tests for these changes

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components/script/dom/cssstylesheet.rs

@@ -5,7 +5,7 @@
 use dom::bindings::codegen::Bindings::CSSStyleSheetBinding;
 use dom::bindings::codegen::Bindings::CSSStyleSheetBinding::CSSStyleSheetMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowBinding::WindowMethods;
-use dom::bindings::error::{ErrorResult, Fallible};
+use dom::bindings::error::{Error, ErrorResult, Fallible};
 use dom::bindings::js::{JS, MutNullableJS, Root};
 use dom::bindings::reflector::{reflect_dom_object, DomObject};
 use dom::bindings::str::DOMString;
@@ -13,6 +13,7 @@ use dom::cssrulelist::{CSSRuleList, RulesSource};
 use dom::element::Element;
 use dom::stylesheet::StyleSheet;
 use dom::window::Window;
+use std::cell::Cell;
 use std::sync::Arc;
 use style::stylesheets::Stylesheet as StyleStyleSheet;
 
@@ -23,6 +24,7 @@ pub struct CSSStyleSheet {
     rulelist: MutNullableJS<CSSRuleList>,
     #[ignore_heap_size_of = "Arc"]
     style_stylesheet: Arc<StyleStyleSheet>,
+    origin_clean: Cell<bool>,
 }
 
 impl CSSStyleSheet {
@@ -36,6 +38,7 @@ impl CSSStyleSheet {
             owner: JS::from_ref(owner),
             rulelist: MutNullableJS::new(None),
             style_stylesheet: stylesheet,
+            origin_clean: Cell::new(true),
         }
     }
 
@@ -71,25 +74,34 @@ impl CSSStyleSheet {
     pub fn style_stylesheet(&self) -> &StyleStyleSheet {
         &self.style_stylesheet
     }
+
+    pub fn set_origin_clean(&self, origin_clean: bool) {
+        self.origin_clean.set(origin_clean);
+    }
 }
 
 impl CSSStyleSheetMethods for CSSStyleSheet {
     // https://drafts.csswg.org/cssom/#dom-cssstylesheet-cssrules
-    fn CssRules(&self) -> Root<CSSRuleList> {
-        // XXXManishearth check origin clean flag
-        // https://github.com/servo/servo/issues/14327
-        self.rulelist()
+    fn GetCssRules(&self) -> Fallible<Root<CSSRuleList>> {
+        if !self.origin_clean.get() {
+            return Err(Error::Security);
+        }
+        Ok(self.rulelist())
     }
 
     // https://drafts.csswg.org/cssom/#dom-cssstylesheet-insertrule
     fn InsertRule(&self, rule: DOMString, index: u32) -> Fallible<u32> {
-        // XXXManishearth check origin clean flag
+        if !self.origin_clean.get() {
+            return Err(Error::Security);
+        }
         self.rulelist().insert_rule(&rule, index, /* nested */ false)
     }
 
     // https://drafts.csswg.org/cssom/#dom-cssstylesheet-deleterule
     fn DeleteRule(&self, index: u32) -> ErrorResult {
-        // XXXManishearth check origin clean flag
+        if !self.origin_clean.get() {
+            return Err(Error::Security);
+        }
         self.rulelist().remove_rule(index)
     }
 }

components/script/dom/htmllinkelement.rs

@@ -319,6 +319,12 @@ impl StylesheetOwner for HTMLLinkElement {
 
         None
     }
+
+    fn set_origin_clean(&self, origin_clean: bool) {
+        if let Some(stylesheet) = self.get_cssom_stylesheet() {
+            stylesheet.set_origin_clean(origin_clean);
+        }
+    }
 }
 
 impl HTMLLinkElementMethods for HTMLLinkElement {

components/script/dom/htmlstyleelement.rs

@@ -191,6 +191,12 @@ impl StylesheetOwner for HTMLStyleElement {
     fn referrer_policy(&self) -> Option<ReferrerPolicy> {
         None
     }
+
+    fn set_origin_clean(&self, origin_clean: bool) {
+        if let Some(stylesheet) = self.get_cssom_stylesheet() {
+            stylesheet.set_origin_clean(origin_clean);
+        }
+    }
 }
 
 

components/script/dom/webidls/CSSStyleSheet.webidl

@@ -6,7 +6,7 @@
 [Exposed=Window]
 interface CSSStyleSheet : StyleSheet {
   // readonly attribute CSSRule? ownerRule;
-  [SameObject] readonly attribute CSSRuleList cssRules;
+  [Throws, SameObject] readonly attribute CSSRuleList cssRules;
   [Throws] unsigned long insertRule(DOMString rule, unsigned long index);
   [Throws] void deleteRule(unsigned long index);
 };