SVGTests should not leave detached elements in the tree

LayoutTests/svg/dynamic-updates/script-tests/SVGLineElement-dom-requiredFeatures.js

Index: LayoutTests/svg/dynamic-updates/script-tests/SVGLineElement-dom-requiredFeatures.js
diff --git a/LayoutTests/svg/dynamic-updates/script-tests/SVGLineElement-dom-requiredFeatures.js b/LayoutTests/svg/dynamic-updates/script-tests/SVGLineElement-dom-requiredFeatures.js
index cf1d9f23cc5d0cb07168eddfe6f40305cef8c58c..52f1eae0f673d9c5e694c25afb8da47cded87d8d 100644
--- a/LayoutTests/svg/dynamic-updates/script-tests/SVGLineElement-dom-requiredFeatures.js
+++ b/LayoutTests/svg/dynamic-updates/script-tests/SVGLineElement-dom-requiredFeatures.js
@@ -15,19 +15,19 @@ rootSVGElement.appendChild(lineElement);
 
 function repaintTest() {
     debug("Check that SVGLineElement is initially displayed");
-    shouldBeEqualToString("document.defaultView.getComputedStyle(lineElement, null).display", "inline");
+    shouldHaveBBox("lineElement", "180", "180");
     debug("Check that setting requiredFeatures to something invalid makes it not render");
     lineElement.setAttribute("requiredFeatures", "http://www.w3.org/TR/SVG11/feature#BogusFeature");
-    shouldBeEqualToString("document.defaultView.getComputedStyle(lineElement, null).display", "");
+    shouldHaveBBox("lineElement", "0", "0");
     debug("Check that setting requiredFeatures to something valid makes it render again");
     lineElement.setAttribute("requiredFeatures", "http://www.w3.org/TR/SVG11/feature#Shape");
-    shouldBeEqualToString("document.defaultView.getComputedStyle(lineElement, null).display", "inline");
+    shouldHaveBBox("lineElement", "180", "180");
     debug("Check that adding something valid to requiredFeatures keeps rendering the element");
     lineElement.setAttribute("requiredFeatures", "http://www.w3.org/TR/SVG11/feature#Gradient");
-    shouldBeEqualToString("document.defaultView.getComputedStyle(lineElement, null).display", "inline");
+    shouldHaveBBox("lineElement", "180", "180");
     debug("Check that adding something invalid to requiredFeatures makes it not render");
     lineElement.setAttribute("requiredFeatures", "http://www.w3.org/TR/SVG11/feature#BogusFeature");
-    shouldBeEqualToString("document.defaultView.getComputedStyle(lineElement, null).display", "");
+    shouldHaveBBox("lineElement", "0", "0");
 
     completeTest();
 }