Remove custom elements examples, they are no longer maintained

sky/examples/widgets/widget-root.sky

Index: sky/examples/widgets/widget-root.sky
diff --git a/sky/examples/widgets/widget-root.sky b/sky/examples/widgets/widget-root.sky
deleted file mode 100644
index cc0d5fab0b40ea6efb25b8cc0b77fcbd2b188df0..0000000000000000000000000000000000000000
--- a/sky/examples/widgets/widget-root.sky
+++ /dev/null
@@ -1,98 +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.
--->
-<import src="/sky/framework/elements/sky-box.sky" />
-<import src="/sky/framework/elements/sky-button.sky" />
-<import src="/sky/framework/elements/sky-checkbox.sky" />
-<import src="/sky/framework/elements/sky-element.sky" />
-<import src="/sky/framework/elements/sky-input.sky" />
-<import src="/sky/framework/elements/sky-radio.sky" />
-<import src="/sky/framework/elements/sky-scrollable.sky" />
-<sky-element>
-<template>
-  <style>
-  :host {
-    font-family: 'Roboto Regular', 'Helvetica';
-  }
-  div {
-    display: flex;
-    align-items: center;
-  }
-  sky-checkbox {
-    margin: 5px;
-  }
-  .output {
-    margin-left: 48px;
-  }
-  sky-scrollable {
-    height: -webkit-fill-available;
-  }
-  </style>
-  <sky-scrollable>
-    <sky-box title='Text'>
-      <sky-input id="text" value="{{ inputValue }}" />
-      <div>value = {{ inputValue }}</div>
-    </sky-box>
-
-    <sky-box title='Buttons'>
-      <div style="display: flex; flex-direction: horizontal">
-        <div style="flex:1" />
-        <sky-button level="1" id="button">CANCEL</sky-button>
-        <sky-button level="1" primary>CONFIRM</sky-button>
-      </div>
-    </sky-box>
-
-    <sky-box title='Checkboxes'>
-      <div><sky-checkbox id='checkbox' checked='{{ checked }}'/>Checkbox</div>
-      <div class="output">highlight: {{ myCheckbox.highlight }}</div>
-      <div class="output">checked: {{ myCheckbox.checked }}</div>
-      <div><sky-checkbox id='checkbox' checked="true"/>Checkbox, default checked.</div>
-      <div class="output">checked: {{ checked }}</div>
-    </sky-box>
-
-    <sky-box title='Radios'>
-      <sky-box title='Group One'>
-        <div><sky-radio group='foo'/>one</div>
-        <div><sky-radio group='foo' selected='true' />two</div>
-        <div><sky-radio group='foo'/>three</div>
-      </sky-box>
-      <sky-box title='Group Two'>
-        <div><sky-radio group='bar'/>A</div>
-        <div><sky-radio group='bar'/>B</div>
-        <div><sky-radio group='bar' selected='true' />C</div>
-      </sky-box>
-    </sky-box>
-  </sky-scrollable>
-</template>
-<script>
-import "dart:sky";
-
-@Tagname('widget-root')
-class WidgetRoot extends SkyElement {
-  Element _button;
-  Element _checkbox;
-  Element _text;
-  int _clickCount = 0;
-  String _inputValue = "Ready";
-  bool _checked = false;
-
-  void shadowRootReady() {
-    _button = this.shadowRoot.getElementById('button');
-    _checkbox = this.shadowRoot.getElementById('checkbox');
-    _text = this.shadowRoot.getElementById('text');
-
-    _button.addEventListener('click', _handleClick);
-  }
-
-  void _handleClick(_) {
-    _clickCount++;
-    _checked = !_checked;
-    _inputValue = "Moar clicking ${_clickCount}";
-  }
-}
-
-_init(script) => register(script, WidgetRoot);
-</script>
-</sky-element>