Bug 1694741 - Part 1: Support width and height attributes in HTMLSourceElement's webidl. r=emilio

This also introduce a pref which protect these two attributes:
dom.picture_source_dimension_attributes.enabled.

These two dimension attributes will be mapped to the style of <img> elements
if the <source> element's parent is <picture>. This will be implemented
in the later patch. For now, we just implement the DOM interface.

Differential Revision: https://phabricator.services.mozilla.com/D152585

dom/html/HTMLSourceElement.cpp

@@ -68,6 +68,20 @@ void HTMLSourceElement::UpdateMediaList(const nsAttrValue* aValue) {
   mMediaList = MediaList::Create(mediaStr);
 }
 
+bool HTMLSourceElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+                                       const nsAString& aValue,
+                                       nsIPrincipal* aMaybeScriptedPrincipal,
+                                       nsAttrValue& aResult) {
+  if (StaticPrefs::dom_picture_source_dimension_attributes_enabled() &&
+      aNamespaceID == kNameSpaceID_None &&
+      (aAttribute == nsGkAtoms::width || aAttribute == nsGkAtoms::height)) {
+    return aResult.ParseHTMLDimension(aValue);
+  }
+
+  return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
+                                              aMaybeScriptedPrincipal, aResult);
+}
+
 nsresult HTMLSourceElement::AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
                                          const nsAttrValue* aValue,
                                          const nsAttrValue* aOldValue,

dom/html/HTMLSourceElement.h

@@ -87,18 +87,31 @@ class HTMLSourceElement final : public nsGenericHTMLElement {
     SetHTMLAttr(nsGkAtoms::media, aMedia, rv);
   }
 
+  uint32_t Width() const { return GetUnsignedIntAttr(nsGkAtoms::width, 0); }
+  void SetWidth(uint32_t aWidth, ErrorResult& aRv) {
+    SetUnsignedIntAttr(nsGkAtoms::width, aWidth, 0, aRv);
+  }
+
+  uint32_t Height() const { return GetUnsignedIntAttr(nsGkAtoms::height, 0); }
+  void SetHeight(uint32_t aHeight, ErrorResult& aRv) {
+    SetUnsignedIntAttr(nsGkAtoms::height, aHeight, 0, aRv);
+  }
+
  protected:
   virtual ~HTMLSourceElement();
 
-  virtual JSObject* WrapNode(JSContext* aCx,
-                             JS::Handle<JSObject*> aGivenProto) override;
+  JSObject* WrapNode(JSContext* aCx,
+                     JS::Handle<JSObject*> aGivenProto) override;
 
- protected:
-  virtual nsresult AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
-                                const nsAttrValue* aValue,
-                                const nsAttrValue* aOldValue,
-                                nsIPrincipal* aMaybeScriptedPrincipal,
-                                bool aNotify) override;
+  bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+                      const nsAString& aValue,
+                      nsIPrincipal* aMaybeScriptedPrincipal,
+                      nsAttrValue& aResult) override;
+
+  nsresult AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
+                        const nsAttrValue* aValue, const nsAttrValue* aOldValue,
+                        nsIPrincipal* aMaybeScriptedPrincipal,
+                        bool aNotify) override;
 
  private:
   RefPtr<MediaList> mMediaList;

dom/webidl/HTMLSourceElement.webidl

@@ -28,4 +28,10 @@ partial interface HTMLSourceElement {
            attribute DOMString sizes;
            [CEReactions, SetterThrows]
            attribute DOMString media;
+           [CEReactions, SetterThrows,
+            Pref="dom.picture_source_dimension_attributes.enabled"]
+           attribute unsigned long width;
+           [CEReactions, SetterThrows,
+            Pref="dom.picture_source_dimension_attributes.enabled"]
+           attribute unsigned long height;
 };

modules/libpref/init/StaticPrefList.yaml

@@ -3132,6 +3132,13 @@
   value: false
   mirror: always
 
+# This enables width and height attributes and map these attributes to img
+# element's style.
+- name: dom.picture_source_dimension_attributes.enabled
+  type: bool
+  value: false
+  mirror: always
+
 # Is support for Element.requestPointerLock enabled?
 # This is added for accessibility purpose. When user has no way to exit
 # pointer lock (e.g. no keyboard available), they can use this pref to

testing/web-platform/meta/html/dom/idlharness.https.html.ini

@@ -1,4 +1,4 @@
-prefs: [dom.security.featurePolicy.experimental.enabled:true, dom.security.featurePolicy.header.enabled:true, dom.security.featurePolicy.webidl.enabled:true, dom.forms.inputmode:true, dom.forms.enterkeyhint:true, dom.forms.autocapitalize:true, html5.inert.enabled:true]
+prefs: [dom.security.featurePolicy.experimental.enabled:true, dom.security.featurePolicy.header.enabled:true, dom.security.featurePolicy.webidl.enabled:true, dom.forms.inputmode:true, dom.forms.enterkeyhint:true, dom.forms.autocapitalize:true, html5.inert.enabled:true, dom.picture_source_dimension_attributes.enabled:true]
 [idlharness.https.html?exclude=(Document|Window|HTML.*)]
   [AudioTrack interface: existence and properties of interface prototype object]
     expected: FAIL
@@ -677,18 +677,6 @@ prefs: [dom.security.featurePolicy.experimental.enabled:true, dom.security.featu
   [HTMLIFrameElement interface: attribute loading]
     expected: FAIL
 
-  [HTMLSourceElement interface: attribute width]
-    expected: FAIL
-
-  [HTMLSourceElement interface: attribute height]
-    expected: FAIL
-
-  [HTMLSourceElement interface: document.createElement("source") must inherit property "width" with the proper type]
-    expected: FAIL
-
-  [HTMLSourceElement interface: document.createElement("source") must inherit property "height" with the proper type]
-    expected: FAIL
-
   [HTMLIFrameElement interface: document.createElement("iframe") must inherit property "loading" with the proper type]
     expected: FAIL