Issue 7720: Add target selector and update when scrolling to fragment

components/script/dom/document.rs

@@ -241,6 +241,8 @@ pub struct Document {
     referrer_policy: Cell<Option<ReferrerPolicy>>,
     /// https://html.spec.whatwg.org/multipage/#dom-document-referrer
     referrer: Option<String>,
+    /// https://html.spec.whatwg.org/multipage/#target-element
+    target_element: MutNullableHeap<JS<Element>>,
 }
 
 #[derive(JSTraceable, HeapSizeOf)]
@@ -1735,6 +1737,7 @@ impl Document {
             origin: origin,
             referrer: referrer,
             referrer_policy: Cell::new(referrer_policy),
+            target_element: MutNullableHeap::new(None),
         }
     }
 
@@ -1886,6 +1889,22 @@ impl Document {
     pub fn get_referrer_policy(&self) -> Option<ReferrerPolicy> {
         return self.referrer_policy.get();
     }
+
+    pub fn set_target_element(&self, node: Option<&Element>) {
+        if let Some(ref element) = self.target_element.get() {
+            element.set_target_state(false);
+        }
+
+        self.target_element.set(node);
+
+        if let Some(ref element) = self.target_element.get() {
+            element.set_target_state(true);
+        }
+
+        self.window.reflow(ReflowGoal::ForDisplay,
+                           ReflowQueryType::NoQuery,
+                           ReflowReason::ElementStateChanged);
+    }
 }
 
 

components/script/dom/element.rs

@@ -2324,7 +2324,8 @@ impl<'a> ::selectors::Element for Root<Element> {
             NonTSPseudoClass::Checked |
             NonTSPseudoClass::Indeterminate |
             NonTSPseudoClass::ReadWrite |
-            NonTSPseudoClass::PlaceholderShown =>
+            NonTSPseudoClass::PlaceholderShown |
+            NonTSPseudoClass::Target =>
                 Element::state(self).contains(pseudo_class.state_flag()),
         }
     }
@@ -2586,6 +2587,14 @@ impl Element {
             self.upcast::<Node>().dirty(NodeDamage::OtherNodeDamage);
         }
     }
+
+    pub fn target_state(&self) -> bool {
+        self.state.get().contains(IN_TARGET_STATE)
+    }
+
+    pub fn set_target_state(&self, value: bool) {
+       self.set_state(IN_TARGET_STATE, value)
+    }
 }
 
 impl Element {