Move fragment navigation into Document object

Move the `check_and_scroll_fragment()` method into Document, make the
mothod set the fragment of url after navigation, and use the
`perform_a_scroll()` method to scroll rather than an individual
method. Also removes the broken `Window.fragment` fields.

1 files changed, 40 insertions, 1 deletions

diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 4d3513b6d96..fac64cbc965 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -18,7 +18,7 @@ use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::codegen::Bindings::NodeFilterBinding::NodeFilter;
 use dom::bindings::codegen::Bindings::PerformanceBinding::PerformanceMethods;
 use dom::bindings::codegen::Bindings::TouchBinding::TouchMethods;
-use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
+use dom::bindings::codegen::Bindings::WindowBinding::{ScrollBehavior, WindowMethods};
 use dom::bindings::codegen::UnionTypes::NodeOrString;
 use dom::bindings::error::{Error, ErrorResult, Fallible};
 use dom::bindings::inheritance::{Castable, ElementTypeId, HTMLElementTypeId, NodeTypeId};
@@ -600,6 +600,45 @@ impl Document {
         }
     }
 
+    /// https://html.spec.whatwg.org/multipage/#scroll-to-the-fragment-identifier
+    pub fn check_and_scroll_fragment(&self, fragment: &str) {
+        let target = self.find_fragment_node(fragment);
+
+        // Step 1
+        self.set_target_element(target.r());
+
+        let point = if fragment.is_empty() || fragment.to_lowercase() == "top" {
+            // FIXME(stshine): this should be the origin of the stacking context space,
+            // which may differ under the influence of writing mode.
+            Some((0.0, 0.0))
+        } else {
+            target.r().map(|element| {
+                // FIXME(#8275, pcwalton): This is pretty bogus when multiple layers
+                // are involved. Really what needs to happen is that this needs to go
+                // through layout to ask which layer the element belongs to, and have
+                // it send the scroll message to the compositor.
+                let rect = element.upcast::<Node>().bounding_content_box();
+
+                // In order to align with element edges, we snap to unscaled pixel
+                // boundaries, since the paint thread currently does the same for
+                // drawing elements. This is important for pages that require pixel
+                // perfect scroll positioning for proper display (like Acid2). Since
+                // we don't have the device pixel ratio here, this might not be
+                // accurate, but should work as long as the ratio is a whole number.
+                // Once #8275 is fixed this should actually take into account the
+                // real device pixel ratio.
+                (rect.origin.x.to_nearest_px() as f32,
+                 rect.origin.y.to_nearest_px() as f32)
+            })
+        };
+
+        if let Some((x, y)) = point {
+            // Step 3
+            self.window.perform_a_scroll(x, y, ScrollBehavior::Instant,
+                                         target.r());
+        }
+    }
+
     fn get_anchor_by_name(&self, name: &str) -> Option<Root<Element>> {
         let check_anchor = |node: &HTMLAnchorElement| {
             let elem = node.upcast::<Element>();