Invalidate visited state changes for svg links.

third_party/WebKit/LayoutTests/svg/css/anchor-change-href.svg

+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+    <style>
+        :link { fill: red }
+        :visited { fill: green }
+    </style>
+    <a xlink:href="http://notvisited" name="x">
+        <text x="20" y="40">This text should be green</text>
+    </a>
+    <text x="20" y="60" id="result1">Not run (requires window.internals).</text>
+    <script>
+        if (window.testRunner) {
+            testRunner.dumpAsText();
+            testRunner.waitUntilDone();
+        }
+
+        window.location.hash = "#x";
+
+        requestAnimationFrame(function(){
+
+            // Change href from non-visited to visited link.
+            getComputedStyle(document.documentElement);
+            document.querySelector("a").setAttribute("xlink:href", "#x");
+
+            if (window.internals) {
+                var resultText = document.getElementById("result1").firstChild;
+                var elementCount = internals.updateStyleAndReturnAffectedElementCount();
+
+                // The elementCount should have been 2, but visited links are

[fs, 2015/12/01 13:32:58]

This has a dodgy feel to it, but I guess we can pray that it doesn't cause
troubles down the line...

+                // not recognized in content_shell, thus the text color doesn't
+                // change and an inheritance propagation to text element is not
+                // necessary. Running this test in Chrome will cause a 2-element
+                // recalc and green text as expected.
+                if (elementCount == 1)
+                    resultText.data = "PASS";
+                else
+                    resultText.data = "FAIL: " + elementCount;
+            }
+
+            if (window.testRunner)
+                testRunner.notifyDone();
+        });
+    </script>
+</svg>