script: Rename bounding_content_box to bounding_content_box_or_zero.

And make bounding_content_box preserve whether the element is rendered.

components/script/dom/document.rs

@@ -625,7 +625,7 @@ impl Document {
             // 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();
+            let rect = element.upcast::<Node>().bounding_content_box_or_zero();
 
             // 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

components/script/dom/element.rs

@@ -1604,7 +1604,7 @@ impl ElementMethods for Element {
     // https://drafts.csswg.org/cssom-view/#dom-element-getboundingclientrect
     fn GetBoundingClientRect(&self) -> Root<DOMRect> {
         let win = window_from_node(self);
-        let rect = self.upcast::<Node>().bounding_content_box();
+        let rect = self.upcast::<Node>().bounding_content_box_or_zero();
         DOMRect::new(win.upcast(),
                      rect.origin.x.to_f64_px(),
                      rect.origin.y.to_f64_px(),

components/script/dom/htmlanchorelement.rs

@@ -544,7 +544,7 @@ impl Activatable for HTMLAnchorElement {
         if let Some(element) = target.downcast::<Element>() {
             if target.is::<HTMLImageElement>() && element.has_attribute(&local_name!("ismap")) {
                 let target_node = element.upcast::<Node>();
-                let rect = target_node.bounding_content_box();
+                let rect = target_node.bounding_content_box_or_zero();
                 ismap_suffix = Some(
                     format!("?{},{}", mouse_event.ClientX().to_f32().unwrap() - rect.origin.x.to_f32_px(),
                                       mouse_event.ClientY().to_f32().unwrap() - rect.origin.y.to_f32_px())

components/script/dom/htmlimageelement.rs

@@ -358,7 +358,7 @@ impl HTMLImageElementMethods for HTMLImageElement {
     // https://html.spec.whatwg.org/multipage/#dom-img-width
     fn Width(&self) -> u32 {
         let node = self.upcast::<Node>();
-        let rect = node.bounding_content_box();
+        let rect = node.bounding_content_box_or_zero();
         rect.size.width.to_px() as u32
     }
 
@@ -370,7 +370,7 @@ impl HTMLImageElementMethods for HTMLImageElement {
     // https://html.spec.whatwg.org/multipage/#dom-img-height
     fn Height(&self) -> u32 {
         let node = self.upcast::<Node>();
-        let rect = node.bounding_content_box();
+        let rect = node.bounding_content_box_or_zero();
         rect.size.height.to_px() as u32
     }
 

components/script/dom/node.rs

@@ -526,10 +526,13 @@ impl Node {
 
     /// Returns the rendered bounding content box if the element is rendered,
     /// and none otherwise.
-    pub fn bounding_content_box(&self) -> Rect<Au> {
+    pub fn bounding_content_box(&self) -> Option<Rect<Au>> {
         window_from_node(self)
             .content_box_query(self.to_trusted_node_address())
-            .unwrap_or_else(Rect::zero)
+    }
+
+    pub fn bounding_content_box_or_zero(&self) -> Rect<Au> {
+        self.bounding_content_box().unwrap_or_else(Rect::zero)
     }
 
     pub fn content_boxes(&self) -> Vec<Rect<Au>> {

components/script/dom/window.rs

@@ -970,7 +970,7 @@ impl Window {
         let body = self.Document().GetBody();
         let (x, y) = match body {
             Some(e) => {
-                let content_size = e.upcast::<Node>().bounding_content_box();
+                let content_size = e.upcast::<Node>().bounding_content_box_or_zero();
                 let content_height = content_size.size.height.to_f64_px();
                 let content_width = content_size.size.width.to_f64_px();
                 (xfinite.max(0.0f64).min(content_width - width),