Check HTMLness of <select> and <selectedcontent> in BrowserTreeBuilder

The other tree builder subclasses (DOMTreeBuilder, XOMTreeBuilder,
SAXTreeBuilder) all verify that <select> and <selectedcontent> elements
are in the HTML namespace before performing <option> cloning. Without
that check, SVG elements with the same local names could incorrectly
trigger the cloning logic.

Author: sideshowbarker

gwt-src/nu/validator/htmlparser/gwt/BrowserTreeBuilder.java

@@ -485,6 +485,11 @@ private static native String getLocalName(
                         return node.localName;
                     }-*/;
 
+    private static native String getNamespaceURI(
+            JavaScriptObject node) /*-{
+                        return node.namespaceURI;
+                    }-*/;
+
     private static native boolean hasAttribute(
             JavaScriptObject node, String name) /*-{
                         return node.hasAttribute(name);
@@ -500,7 +505,9 @@ protected void optionElementPopped(JavaScriptObject option)
             JavaScriptObject ancestor = getParentNode(option);
             JavaScriptObject select = null;
             while (ancestor != null && getNodeType(ancestor) == 1) {
-                if ("select".equals(getLocalName(ancestor))) {
+                if ("select".equals(getLocalName(ancestor))
+                        && "http://www.w3.org/1999/xhtml".equals(
+                                getNamespaceURI(ancestor))) {
                     select = ancestor;
                     break;
                 }
@@ -514,8 +521,8 @@ protected void optionElementPopped(JavaScriptObject option)
             }
 
             // Find the first <selectedcontent> descendant of <select>
-            JavaScriptObject selectedContent = findDescendantByLocalName(
-                    select, "selectedcontent");
+            JavaScriptObject selectedContent = findSelectedContent(
+                    select);
             if (selectedContent == null) {
                 return;
             }
@@ -540,16 +547,18 @@ protected void optionElementPopped(JavaScriptObject option)
         }
     }
 
-    private JavaScriptObject findDescendantByLocalName(
-            JavaScriptObject root, String localName) {
+    private JavaScriptObject findSelectedContent(
+            JavaScriptObject root) {
         JavaScriptObject current = getFirstChild(root);
         if (current == null) {
             return null;
         }
         JavaScriptObject next;
         for (;;) {
             if (getNodeType(current) == 1
-                    && localName.equals(getLocalName(current))) {
+                    && "selectedcontent".equals(getLocalName(current))
+                    && "http://www.w3.org/1999/xhtml".equals(
+                            getNamespaceURI(current))) {
                 return current;
             }
             if ((next = getFirstChild(current)) != null) {