Auto merge of #13589 - splav:SVGElement#12974, r=pcwalton,Ms2ger

Support SVG element

<!-- Please describe your changes on the following line: -->
minimal SVG element implementation
---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #12974 (github issue number if applicable).

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- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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components/script/dom/webidls/SVGElement.webidl

@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// https://svgwg.org/svg2-draft/types.html#InterfaceSVGElement
+[Pref="dom.svg.enabled"]
+interface SVGElement : Element {
+
+  //[SameObject] readonly attribute SVGAnimatedString className;
+
+  //[SameObject] readonly attribute DOMStringMap dataset;
+
+  //readonly attribute SVGSVGElement? ownerSVGElement;
+  //readonly attribute SVGElement? viewportElement;
+
+  //attribute long tabIndex;
+  //void focus();
+  //void blur();
+};
+
+//SVGElement implements GlobalEventHandlers;
+//SVGElement implements SVGElementInstance;

components/script/dom/webidls/SVGGraphicsElement.webidl

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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// https://svgwg.org/svg2-draft/types.html#InterfaceSVGGraphicsElement
+[Pref="dom.svg.enabled"]
+//dictionary SVGBoundingBoxOptions {
+//  boolean fill = true;
+//  boolean stroke = false;
+//  boolean markers = false;
+//  boolean clipped = false;
+//};
+
+interface SVGGraphicsElement : SVGElement {
+  //[SameObject] readonly attribute SVGAnimatedTransformList transform;
+
+  //DOMRect getBBox(optional SVGBoundingBoxOptions options);
+  //DOMMatrix? getCTM();
+  //DOMMatrix? getScreenCTM();
+};
+
+//SVGGraphicsElement implements SVGTests;

components/script/dom/webidls/SVGSVGElement.webidl

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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// https://svgwg.org/svg2-draft/struct.html#InterfaceSVGSVGElement
+[Pref="dom.svg.enabled"]
+interface SVGSVGElement : SVGGraphicsElement {
+
+  //[SameObject] readonly attribute SVGAnimatedLength x;
+  //[SameObject] readonly attribute SVGAnimatedLength y;
+  //[SameObject] readonly attribute SVGAnimatedLength width;
+  //[SameObject] readonly attribute SVGAnimatedLength height;
+
+  //attribute float currentScale;
+  //[SameObject] readonly attribute DOMPointReadOnly currentTranslate;
+
+  //NodeList getIntersectionList(DOMRectReadOnly rect, SVGElement? referenceElement);
+  //NodeList getEnclosureList(DOMRectReadOnly rect, SVGElement? referenceElement);
+  //boolean checkIntersection(SVGElement element, DOMRectReadOnly rect);
+  //boolean checkEnclosure(SVGElement element, DOMRectReadOnly rect);
+
+  //void deselectAll();
+
+  //SVGNumber createSVGNumber();
+  //SVGLength createSVGLength();
+  //SVGAngle createSVGAngle();
+  //DOMPoint createSVGPoint();
+  //DOMMatrix createSVGMatrix();
+  //DOMRect createSVGRect();
+  //SVGTransform createSVGTransform();
+  //SVGTransform createSVGTransformFromMatrix(DOMMatrixReadOnly matrix);
+
+  //Element getElementById(DOMString elementId);
+
+  // Deprecated methods that have no effect when called,
+  // but which are kept for compatibility reasons.
+  //unsigned long suspendRedraw(unsigned long maxWaitMilliseconds);
+  //void unsuspendRedraw(unsigned long suspendHandleID);
+  //void unsuspendRedrawAll();
+  //void forceRedraw();
+};
+
+//SVGSVGElement implements SVGFitToViewBox;
+//SVGSVGElement implements SVGZoomAndPan;
+//SVGSVGElement implements WindowEventHandlers;