Rewrite svg/dynamic-updates to use text-based repaint harness

LayoutTests/svg/dynamic-updates/resources/SVGTestCase.js

Index: LayoutTests/svg/dynamic-updates/resources/SVGTestCase.js
diff --git a/LayoutTests/svg/dynamic-updates/resources/SVGTestCase.js b/LayoutTests/svg/dynamic-updates/resources/SVGTestCase.js
index 90f4ec26c07033d4161e028fa24e4ed57bf6bc67..853efeee75d7e6aa2527bb4e87e4ec10f51faa75 100644
--- a/LayoutTests/svg/dynamic-updates/resources/SVGTestCase.js
+++ b/LayoutTests/svg/dynamic-updates/resources/SVGTestCase.js
@@ -8,6 +8,19 @@ var xhtmlNS = "http://www.w3.org/1999/xhtml";
 var rootSVGElement;
 var iframeElement;
 
+if (window.testRunner) {
+    var s = document.createElement('style');
+    s.innerHTML += ".running h1, .running pre, .running div#console, .running p { display:none }";
+    s.innerHTML += "h1, pre, div#console, p { opacity: 0 }";
+    s.innerHTML += "body { overflow: hidden }";
+    document.head.appendChild(s);
+    document.head.parentNode.classList.add("running");
+}
+
+function afterTest() {
+    document.head.parentNode.classList.remove("running");
+}
+
 function createSVGElement(name) {
     return document.createElementNS(svgNS, "svg:" + name);
 }