diff --git a/engine/core/dom/Document.idl b/engine/core/dom/Document.idl
index 86274037cf7..a111f003b44 100644
--- a/engine/core/dom/Document.idl
+++ b/engine/core/dom/Document.idl
@@ -29,7 +29,7 @@ typedef (CanvasRenderingContext2D or WebGLRenderingContext) RenderingContext;
     [CustomElementCallbacks, RaisesException] Element createElement(DOMString tagName);
     DocumentFragment createDocumentFragment();
 
-    [CustomElementCallbacks, RaisesException, TypeChecking=Interface] Node importNode(Node node, optional boolean deep = false);
+    [CustomElementCallbacks, RaisesException, TypeChecking=Interface] Node importNode(Node node, [Named] optional boolean deep = false);
 
     Element getElementById(DOMString elementId);
 
diff --git a/engine/core/html/parser/HTMLDocumentParser.cpp b/engine/core/html/parser/HTMLDocumentParser.cpp
index 08087fcb885..9f2ab19ed6d 100644
--- a/engine/core/html/parser/HTMLDocumentParser.cpp
+++ b/engine/core/html/parser/HTMLDocumentParser.cpp
@@ -394,11 +394,12 @@ bool HTMLDocumentParser::isWaitingForScripts() const
 
 void HTMLDocumentParser::resumeAfterWaitingForImports()
 {
-    RefPtr<HTMLDocumentParser> protect(this);
-    ASSERT(!isWaitingForScripts());
+    if (isWaitingForScripts())
+        return;
     if (m_pendingChunks.isEmpty())
         return;
     ASSERT(m_haveBackgroundParser);
+    RefPtr<HTMLDocumentParser> protect(this);
     pumpPendingChunks();
 }
 
diff --git a/examples/data/cities.sky b/examples/data/cities.sky
index 32b8bfedcf6..f1bf499c180 100644
--- a/examples/data/cities.sky
+++ b/examples/data/cities.sky
@@ -4,7 +4,7 @@
 // found in the LICENSE file.
 -->
 <script>
-module.exports = [
+final List<Map> kData = [
   {"name":"New York","state":"New York","population":8363710},
   {"name":"Los Angeles","state":"California","population":3833995},
   {"name":"Chicago","state":"Illinois","population":2853114},
diff --git a/examples/example-scrollable.sky b/examples/example-scrollable.sky
deleted file mode 100644
index cd5e60f91f6..00000000000
--- a/examples/example-scrollable.sky
+++ /dev/null
@@ -1,43 +0,0 @@
-#!mojo mojo:sky_viewer
-<!--
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
--->
-<sky>
-<import src="/sky/framework/sky-element/sky-element.sky" as="SkyElement" />
-<import src="/sky/framework/sky-scrollable.sky" />
-<import src="data/cities.sky" as="cities" />
-
-<sky-element name="example-scrollable">
-<template>
-  <style>
-  sky-scrollable {
-    margin: 20px;
-    height: 400px;
-    border: 2px solid blue;
-  }
-  b {
-    display: inline;
-    font-weight: bold;
-  }
-  </style>
-  <sky-scrollable>
-    <template repeat="{{ cities }}">
-      <template>
-        <div>{{ name }}</div>
-      </template>
-    </template>
-  </sky-scrollable>
-</template>
-<script>
-module.exports = class extends SkyElement {
-  created() {
-    this.cities = cities.slice(0, 300);
-  }
-}.register();
-</script>
-</sky-element>
-
-<example-scrollable />
-</sky>
diff --git a/examples/example-scrollable/example-scrollable.sky b/examples/example-scrollable/example-scrollable.sky
new file mode 100644
index 00000000000..c6f27b88215
--- /dev/null
+++ b/examples/example-scrollable/example-scrollable.sky
@@ -0,0 +1,38 @@
+<!--
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+-->
+<import src="/sky/framework/sky-element.sky" />
+<import src="/sky/framework/sky-scrollable.sky" />
+<import src="../data/cities.sky" as="cities" />
+
+<sky-element name="example-scrollable">
+<template>
+  <style>
+  sky-scrollable {
+    margin: 20px;
+    height: 400px;
+    border: 2px solid blue;
+  }
+  </style>
+  <sky-scrollable />
+</template>
+<script>
+import "dart:sky";
+
+@Tagname('example-scrollable')
+class ExampleScrollable extends SkyElement {
+  void shadowRootReady() {
+    Element parent = shadowRoot.querySelector('sky-scrollable');
+    for (Map city in cities.kData.getRange(0, 300)) {
+      Element div = document.createElement('div');
+      div.setChild(new Text(city['name']));
+      parent.appendChild(div);
+    }
+  }
+}
+
+_init(script) => register(script, ExampleScrollable);
+</script>
+</sky-element>
diff --git a/examples/example-scrollable/index.sky b/examples/example-scrollable/index.sky
new file mode 100644
index 00000000000..f71a788e97e
--- /dev/null
+++ b/examples/example-scrollable/index.sky
@@ -0,0 +1,10 @@
+#!mojo mojo:sky_viewer
+<!--
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+-->
+<sky>
+  <import src="example-scrollable.sky" />
+  <example-scrollable />
+</sky>
diff --git a/framework/fling-curve.dart b/framework/fling-curve.dart
new file mode 100644
index 00000000000..6dce624dda8
--- /dev/null
+++ b/framework/fling-curve.dart
@@ -0,0 +1,51 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import "dart:math" as math;
+
+const double _kDefaultAlpha = -5707.62;
+const double _kDefaultBeta = 172.0;
+const double _kDefaultGamma = 3.7;
+
+double _positionAtTime(double t) {
+  return kDefaultAlpha * math.exp(-kDefaultGamma * t) - kDefaultBeta * t - kDefaultAlpha;
+}
+
+double _velocityAtTime(double t) {
+  return -kDefaultAlpha * kDefaultGamma * math.exp(-kDefaultGamma * t) - kDefaultBeta;
+}
+
+double _timeAtVelocity(double v) {
+  return -math.log((v + kDefaultBeta) / (-kDefaultAlpha * kDefaultGamma)) / kDefaultGamma;
+}
+
+final double _kMaxVelocity = _velocityAtTime(0.0);
+final double _kCurveDuration = _timeAtVelocity(0.0);
+
+class FlingCurve {
+  double _timeOffset;
+  double _positionOffset;
+  double _startTime;
+  double _previousPosition;
+  double _direction;
+
+  FlingCurve(double velocity, double startTime) {
+    double startingVelocity = math.min(_kMaxVelocity, velocity.abs());
+    _timeOffset = _velocityAtTime(startingVelocity);
+    _positionOffset = _positionAtTime(_timeOffset);
+    _startTime = startTime / 1000.0;
+    _previousPosition = 0.0;
+    _direction = velocity.sign;
+  }
+
+  double update(double timeStamp) {
+    double t = timeStamp / 1000.0 - _startTime + _timeOffset;
+    if (t >= _kCurveDuration)
+      return 0.0;
+    double position = _positionAtTime(t) - _positionOffset;
+    double positionDelta = position - _previousPosition;
+    _previousPosition = position;
+    return _direction * math.max(0.0, positionDelta);
+  }
+}
diff --git a/framework/fling-curve.sky b/framework/fling-curve.sky
deleted file mode 100644
index 1c13908b4f9..00000000000
--- a/framework/fling-curve.sky
+++ /dev/null
@@ -1,47 +0,0 @@
-<!--
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
--->
-<script>
-const kDefaultAlpha = -5707.62;
-const kDefaultBeta = 172;
-const kDefaultGamma = 3.7;
-
-function positionAtTime(t) {
-  return kDefaultAlpha * Math.exp(-kDefaultGamma * t) - kDefaultBeta * t - kDefaultAlpha;
-}
-
-function velocityAtTime(t) {
-  return -kDefaultAlpha * kDefaultGamma * Math.exp(-kDefaultGamma * t) - kDefaultBeta;
-}
-
-function timeAtVelocity(v) {
-  return -Math.log((v + kDefaultBeta) / (-kDefaultAlpha * kDefaultGamma)) / kDefaultGamma;
-}
-
-var kMaxVelocity = velocityAtTime(0);
-var kCurveDuration = timeAtVelocity(0);
-
-module.exports = class FlingCurve {
-  constructor(velocity, startTime) {
-    var startingVelocity = Math.min(kMaxVelocity, Math.abs(velocity));
-    this.timeOffset_ = timeAtVelocity(startingVelocity);
-    this.positionOffset_ = positionAtTime(this.timeOffset_);
-    this.startTime_ = startTime / 1000;
-    this.previousPosition_ = 0;
-    this.direction_ = Math.sign(velocity);
-    Object.preventExtensions(this);
-  }
-
-  update(timeStamp) {
-    var t = timeStamp / 1000 - this.startTime_ + this.timeOffset_;
-    if (t >= kCurveDuration)
-      return 0;
-    var position = positionAtTime(t) - this.positionOffset_;
-    var positionDelta = position - this.previousPosition_;
-    this.previousPosition_ = position;
-    return this.direction_ * Math.max(0, positionDelta);
-  }
-};
-</script>
diff --git a/framework/sky-element.sky b/framework/sky-element.sky
index 8b04f79a504..2fdc62ad65d 100644
--- a/framework/sky-element.sky
+++ b/framework/sky-element.sky
@@ -47,8 +47,8 @@ abstract class SkyElement extends Element {
       var registration = _registery[tagName];
       if (registration.template != null) {
         ShadowRoot shadow = ensureShadowRoot();
-        var tree = registration.template.content.cloneNode(deep:true);
-        shadow.appendChild(tree);
+        Node content = registration.template.content;
+        shadow.appendChild(document.importNode(content, deep: true));
         shadowRootReady();
       }
     }
diff --git a/framework/sky-scrollable.sky b/framework/sky-scrollable.sky
index 9e369196a98..e0292d1d1ca 100644
--- a/framework/sky-scrollable.sky
+++ b/framework/sky-scrollable.sky
@@ -3,17 +3,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 -->
-<import src="sky-element/sky-element.sky" as="SkyElement" />
-<import src="fling-curve.sky" as="FlingCurve" />
+<import src="sky-element.sky" />
 
-<sky-element
-  name="sky-scrollable"
-  on-gesturescrollstart="handleScrollStart_"
-  on-gesturescrollend="handleScrollEnd_"
-  on-gesturescrollupdate="handleScrollUpdate_"
-  on-gestureflingstart="handleFlingStart_"
-  on-gestureflingcancel="handleFlingCancel_"
-  on-wheel="handleWheel_">
+<sky-element>
 <template>
   <style>
   :host {
@@ -42,90 +34,103 @@
   <div id="vbar" />
 </template>
 <script>
-module.exports = class extends SkyElement {
-  created() {
-    this.scrollable_ = null;
-    this.vbar_ = null;
-    this.scrollOffset_ = 0;
-    this.flingCurve_ = null;
-    this.flingAnimationId_ = null;
+import "dart:math" as math;
+import "dart:sky";
+import "fling-curve.dart";
+
+@Tagname('sky-scrollable')
+class SkyScrollable extends SkyElement {
+  Element _scrollable;
+  Element _vbar;
+  double _scrollOffset = 0.0;
+  FlingCurve _flingCurve;
+  int _flingAnimationId;
+
+  SkyScrollable() {
+    addEventListener('gesturescrollstart', _handleScrollStart);
+    addEventListener('gesturescrollend', _handleScrollEnd);
+    addEventListener('gesturescrollupdate', _handleScrollUpdate);
+    addEventListener('gestureflingstart', _handleFlingStart);
+    addEventListener('gestureflingcancel', _handleFlingCancel);
+    addEventListener('wheel', _handleWheel);
   }
 
-  shadowRootReady() {
-    this.scrollable_ = this.shadowRoot.getElementById('scrollable');
-    this.vbar_ = this.shadowRoot.getElementById('vbar');
+  void shadowRootReady() {
+    _scrollable = shadowRoot.getElementById('scrollable');
+    _vbar = shadowRoot.getElementById('vbar');
   }
 
-  get scrollOffset() {
-    return this.scrollOffset_;
-  }
+  double get scrollOffset => _scrollOffset;
 
-  set scrollOffset(value) {
+  set scrollOffset(double value) {
     // TODO(abarth): Can we get these values without forcing a synchronous layout?
-    var outerHeight = this.clientHeight;
-    var innerHeight = this.scrollable_.clientHeight;
-    var scrollRange = innerHeight - outerHeight;
-    var newScrollOffset = Math.max(0, Math.min(scrollRange, value));
-    if (newScrollOffset == this.scrollOffset_)
+    double outerHeight = clientHeight.toDouble();
+    double innerHeight = _scrollable.clientHeight.toDouble();
+    double scrollRange = innerHeight - outerHeight;
+    double newScrollOffset = math.max(0.0, math.min(scrollRange, value));
+    if (newScrollOffset == _scrollOffset)
       return;
-    this.scrollOffset_ = newScrollOffset;
-    var transform = 'translateY(' + -this.scrollOffset_.toFixed(2) + 'px)';
-    this.scrollable_.style.transform = transform;
+    _scrollOffset = newScrollOffset;
+    String transform = 'translateY(${(-_scrollOffset).toStringAsFixed(2)}px)';
+    _scrollable.style['transform'] = transform;
 
-    var topPercent = newScrollOffset / innerHeight * 100;
-    var heightPercent = outerHeight / innerHeight * 100;
-    this.vbar_.style.top = topPercent + '%';
-    this.vbar_.style.height = heightPercent + '%';
+    double topPercent = newScrollOffset / innerHeight * 100.0;
+    double heightPercent = outerHeight / innerHeight * 100.0;
+    _vbar.style['top'] = '${topPercent}%';
+    _vbar.style['height'] = '${heightPercent}%';
   }
 
-  scrollBy(scrollDelta) {
-    var oldScrollOffset = this.scrollOffset_;
-    this.scrollOffset += scrollDelta;
-    return this.scrollOffset_ != oldScrollOffset;
+  bool scrollBy(double scrollDelta) {
+    double oldScrollOffset = _scrollOffset;
+    scrollOffset += scrollDelta;
+    return _scrollOffset != oldScrollOffset;
   }
 
-  scheduleFlingUpdate_() {
-    this.flingAnimationId_ = requestAnimationFrame(this.updateFling_.bind(this));
+  void _scheduleFlingUpdate() {
+    _flingAnimationId = window.requestAnimationFrame(_updateFling);
   }
 
-  stopFling_() {
-    cancelAnimationFrame(this.flingAnimationId_);
-    this.flingCurve_ = null;
-    this.flingAnimationId_ = null;
-    this.vbar_.style.opacity = 0;
+  void _stopFling() {
+    window.cancelAnimationFrame(_flingAnimationId);
+    _flingCurve = null;
+    _flingAnimationId = null;
+    _vbar.style['opacity'] = '0';
   }
 
-  updateFling_(timeStamp) {
-    var scrollDelta = this.flingCurve_.update(timeStamp);
-    if (!scrollDelta || !this.scrollBy(scrollDelta))
-      return this.stopFling_();
-    this.scheduleFlingUpdate_();
+  void _updateFling(double timeStamp) {
+    double scrollDelta = _flingCurve.update(timeStamp);
+    if (scrollDelta == 0.0 || !scrollBy(scrollDelta))
+      _stopFling();
+    else
+      _scheduleFlingUpdate();
   }
 
-  handleScrollStart_(event) {
-    this.vbar_.style.opacity = 1;
+  void _handleScrollStart(_) {
+    _vbar.style['opacity'] = '1';
   }
 
-  handleScrollEnd_(event) {
-    this.vbar_.style.opacity = 0;
+  void _handleScrollEnd(_) {
+    _vbar.style['opacity'] = '0';
   }
 
-  handleScrollUpdate_(event) {
-    this.scrollBy(-event.dy);
+  void _handleScrollUpdate(GestureEvent event) {
+    scrollBy(-event.dy);
   }
 
-  handleFlingStart_(event) {
-    this.flingCurve_ = new FlingCurve(-event.velocityY, event.timeStamp);
-    this.scheduleFlingUpdate_();
+  void _handleFlingStart(GestureEvent event) {
+    _flingCurve = new FlingCurve(-event.velocityY, event.timeStamp);
+    _scheduleFlingUpdate();
   }
 
-  handleFlingCancel_(event) {
-    this.stopFling_();
+  void _handleFlingCancel(_) {
+    _stopFling();
   }
 
-  handleWheel_(event) {
-    this.scrollBy(-event.offsetY);
+  void _handleWheel(WheelEvent event) {
+    scrollBy(-event.offsetY);
   }
-}.register();
+}
+
+_init(script) => register(script, SkyScrollable);
 </script>
 </sky-element>
diff --git a/tests/custom-elements/callbacks.sky b/tests/custom-elements/callbacks.sky
index b9d640943a6..1f6374d80d2 100644
--- a/tests/custom-elements/callbacks.sky
+++ b/tests/custom-elements/callbacks.sky
@@ -6,7 +6,7 @@ import "../resources/unit.dart";
 import "dart:sky";
 
 class FooElement extends Element {
-  FooElement() : super("foo");
+  final String tagName = "foo";
 
   attachedCallback() {
     ++attachedCallbackCount;
diff --git a/tests/custom-elements/registration.sky b/tests/custom-elements/registration.sky
index 1a2627380d6..c7f7af58ad8 100644
--- a/tests/custom-elements/registration.sky
+++ b/tests/custom-elements/registration.sky
@@ -3,7 +3,7 @@
 import "dart:sky";
 
 class FooElement extends Element {
-  FooElement() : super("foo");
+  final String tagName = "foo";
 
   attachedCallback() {
     print("PASS: FooElement attached.");