fix($sanitize): reduce stack height in IE <= 11

Update Internet Explorer-only helper function stripCustomNsAttrs to be less
recursive. Reduce stack height of function causing out of stack space error.

Closes #14928
Closes #15030

src/ngSanitize/sanitize.js

@@ -499,27 +499,26 @@ function $SanitizeProvider() {
    * @param node Root element to process
    */
   function stripCustomNsAttrs(node) {
-    if (node.nodeType === window.Node.ELEMENT_NODE) {
-      var attrs = node.attributes;
-      for (var i = 0, l = attrs.length; i < l; i++) {
-        var attrNode = attrs[i];
-        var attrName = attrNode.name.toLowerCase();
-        if (attrName === 'xmlns:ns1' || attrName.lastIndexOf('ns1:', 0) === 0) {
-          node.removeAttributeNode(attrNode);
-          i--;
-          l--;
+    while (node) {
+      if (node.nodeType === window.Node.ELEMENT_NODE) {
+        var attrs = node.attributes;
+        for (var i = 0, l = attrs.length; i < l; i++) {
+          var attrNode = attrs[i];
+          var attrName = attrNode.name.toLowerCase();
+          if (attrName === 'xmlns:ns1' || attrName.lastIndexOf('ns1:', 0) === 0) {
+            node.removeAttributeNode(attrNode);
+            i--;
+            l--;
+          }
         }
       }
-    }
 
-    var nextNode = node.firstChild;
-    if (nextNode) {
-      stripCustomNsAttrs(nextNode);
-    }
+      var nextNode = node.firstChild;
+      if (nextNode) {
+        stripCustomNsAttrs(nextNode);
+      }
 
-    nextNode = node.nextSibling;
-    if (nextNode) {
-      stripCustomNsAttrs(nextNode);
+      node = node.nextSibling;
     }
   }
 }

test/ngSanitize/sanitizeSpec.js

@@ -130,6 +130,17 @@ describe('HTML', function() {
     expectHTML('a<div style="abc">b</div>c').toEqual('a<div>b</div>c');
   });
 
+  it('should handle large datasets', function() {
+    // Large is non-trivial to quantify, but handling ~100,000 should be sufficient for most purposes.
+    var largeNumber = 17; // 2^17 = 131,072
+    var result = '<div>b</div>';
+    // Ideally we would use repeat, but that isn't supported in IE.
+    for (var i = 0; i < largeNumber; i++) {
+      result += result;
+    }
+    expectHTML('a' + result + 'c').toEqual('a' + result + 'c');
+  });
+
   it('should remove style', function() {
     expectHTML('a<STyle>evil</stYle>c.').toEqual('ac.');
   });