Auto merge of #15053 - emilio:image-width, r=jdm

Return the intrinsic image dimension when the image is not rendered

See individual commits for details.

r? @jdm

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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

@@ -21,7 +21,7 @@ use dom::eventtarget::EventTarget;
 use dom::htmlelement::HTMLElement;
 use dom::htmlimageelement::HTMLImageElement;
 use dom::mouseevent::MouseEvent;
-use dom::node::{Node, document_from_node, window_from_node};
+use dom::node::{Node, document_from_node};
 use dom::urlhelper::UrlHelper;
 use dom::virtualmethods::VirtualMethods;
 use html5ever_atoms::LocalName;
@@ -544,8 +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 = window_from_node(target_node).content_box_query(
-                    target_node.to_trusted_node_address());
+                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

@@ -358,8 +358,10 @@ 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();
-        rect.size.width.to_px() as u32
+        match node.bounding_content_box() {
+            Some(rect) => rect.size.width.to_px() as u32,
+            None => self.NaturalWidth(),
+        }
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-img-width
@@ -370,8 +372,10 @@ 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();
-        rect.size.height.to_px() as u32
+        match node.bounding_content_box() {
+            Some(rect) => rect.size.height.to_px() as u32,
+            None => self.NaturalHeight(),
+        }
     }
 
     // https://html.spec.whatwg.org/multipage/#dom-img-height

components/script/dom/node.rs

@@ -524,8 +524,15 @@ impl Node {
         TrustedNodeAddress(&*self as *const Node as *const libc::c_void)
     }
 
-    pub fn bounding_content_box(&self) -> Rect<Au> {
-        window_from_node(self).content_box_query(self.to_trusted_node_address())
+    /// Returns the rendered bounding content box if the element is rendered,
+    /// and none otherwise.
+    pub fn bounding_content_box(&self) -> Option<Rect<Au>> {
+        window_from_node(self)
+            .content_box_query(self.to_trusted_node_address())
+    }
+
+    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),
@@ -1216,11 +1216,11 @@ impl Window {
         &*self.layout_rpc
     }
 
-    pub fn content_box_query(&self, content_box_request: TrustedNodeAddress) -> Rect<Au> {
+    pub fn content_box_query(&self, content_box_request: TrustedNodeAddress) -> Option<Rect<Au>> {
         if !self.reflow(ReflowGoal::ForScriptQuery,
                         ReflowQueryType::ContentBoxQuery(content_box_request),
                         ReflowReason::Query) {
-            return Rect::zero();
+            return None;
         }
         let ContentBoxResponse(rect) = self.layout_rpc.content_box();
         rect