sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 34cbd411ea7325c62a6f6997318718bb949572b9..ffe111fb77f0e229957b7f851b48643dc97fa711 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -12895,8 +12895,12 @@ abstract class Element extends Node implements GlobalEventHandlers, ParentNode,
    */
   void insertAdjacentHtml(String where, String html, {NodeValidator validator,
       NodeTreeSanitizer treeSanitizer}) {
-      _insertAdjacentNode(where, new DocumentFragment.html(html,
-          validator: validator, treeSanitizer: treeSanitizer));
+      if (treeSanitizer is _TrustedHtmlTreeSanitizer) {
+        _insertAdjacentHtml(where, html);
+      } else {
+        _insertAdjacentNode(where, new DocumentFragment.html(html,
+            validator: validator, treeSanitizer: treeSanitizer));
+      }
   }
 
 
@@ -13247,8 +13251,12 @@ abstract class Element extends Node implements GlobalEventHandlers, ParentNode,
   void setInnerHtml(String html,
     {NodeValidator validator, NodeTreeSanitizer treeSanitizer}) {
     text = null;
-    append(createFragment(
-        html, validator: validator, treeSanitizer: treeSanitizer));
+    if (treeSanitizer is _TrustedHtmlTreeSanitizer) {
+      _innerHtml = html;
+    } else {
+      append(createFragment(
+          html, validator: validator, treeSanitizer: treeSanitizer));
+    }
   }
   String get innerHtml => _innerHtml;
 
@@ -40692,9 +40700,27 @@ abstract class NodeTreeSanitizer {
    * will mark the entire tree as unsafe.
    */
   void sanitizeTree(Node node);
+
+  /**
+   * A sanitizer for trees that we trust. It does no validation and allows
+   * any elements. It is also more efficient, since it can pass the text
+   * directly through to the underlying APIs without creating a document 
+   * fragment to be sanitized.
+   */
+  static const trusted = const _TrustedHtmlTreeSanitizer();
 }
 
 /**
+ * A sanitizer for trees that we trust. It does no validation and allows
+ * any elements.
+ */
+class _TrustedHtmlTreeSanitizer implements NodeTreeSanitizer {
+  const _TrustedHtmlTreeSanitizer();
+
+  sanitizeTree(Node node) {}
+}
+  
+/**
  * Defines the policy for what types of uris are allowed for particular
  * attribute values.
  *