Revert "Build Observatory with runtime"

runtime/bin/vmservice/observatory/deployed/web/packages/custom_element/custom-elements.debug.js

Index: runtime/bin/vmservice/observatory/deployed/web/packages/custom_element/custom-elements.debug.js
diff --git a/runtime/bin/vmservice/observatory/deployed/web/packages/custom_element/custom-elements.debug.js b/runtime/bin/vmservice/observatory/deployed/web/packages/custom_element/custom-elements.debug.js
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@@ -0,0 +1,984 @@
+// Copyright (c) 2012 The Polymer Authors. All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+if (typeof WeakMap === 'undefined') {
+  (function() {
+    var defineProperty = Object.defineProperty;
+    var counter = Date.now() % 1e9;
+
+    var WeakMap = function() {
+      this.name = '__st' + (Math.random() * 1e9 >>> 0) + (counter++ + '__');
+    };
+
+    WeakMap.prototype = {
+      set: function(key, value) {
+        var entry = key[this.name];
+        if (entry && entry[0] === key)
+          entry[1] = value;
+        else
+          defineProperty(key, this.name, {value: [key, value], writable: true});
+      },
+      get: function(key) {
+        var entry;
+        return (entry = key[this.name]) && entry[0] === key ?
+            entry[1] : undefined;
+      },
+      delete: function(key) {
+        this.set(key, undefined);
+      }
+    };
+
+    window.WeakMap = WeakMap;
+  })();
+}
+
+window.CustomElements = window.CustomElements || {flags:{}};
+(function(scope){
+
+var logFlags = window.logFlags || {};
+var IMPORT_LINK_TYPE = window.HTMLImports ? HTMLImports.IMPORT_LINK_TYPE : 'none';
+
+// walk the subtree rooted at node, applying 'find(element, data)' function
+// to each element
+// if 'find' returns true for 'element', do not search element's subtree
+function findAll(node, find, data) {
+  var e = node.firstElementChild;
+  if (!e) {
+    e = node.firstChild;
+    while (e && e.nodeType !== Node.ELEMENT_NODE) {
+      e = e.nextSibling;
+    }
+  }
+  while (e) {
+    if (find(e, data) !== true) {
+      findAll(e, find, data);
+    }
+    e = e.nextElementSibling;
+  }
+  return null;
+}
+
+// walk all shadowRoots on a given node.
+function forRoots(node, cb) {
+  var root = node.shadowRoot;
+  while(root) {
+    forSubtree(root, cb);
+    root = root.olderShadowRoot;
+  }
+}
+
+// walk the subtree rooted at node, including descent into shadow-roots,
+// applying 'cb' to each element
+function forSubtree(node, cb) {
+  //logFlags.dom && node.childNodes && node.childNodes.length && console.group('subTree: ', node);
+  findAll(node, function(e) {
+    if (cb(e)) {
+      return true;
+    }
+    forRoots(e, cb);
+  });
+  forRoots(node, cb);
+  //logFlags.dom && node.childNodes && node.childNodes.length && console.groupEnd();
+}
+
+// manage lifecycle on added node
+function added(node) {
+  if (upgrade(node)) {
+    insertedNode(node);
+    return true;
+  }
+  inserted(node);
+}
+
+// manage lifecycle on added node's subtree only
+function addedSubtree(node) {
+  forSubtree(node, function(e) {
+    if (added(e)) {
+      return true;
+    }
+  });
+}
+
+// manage lifecycle on added node and it's subtree
+function addedNode(node) {
+  return added(node) || addedSubtree(node);
+}
+
+// upgrade custom elements at node, if applicable
+function upgrade(node) {
+  if (!node.__upgraded__ && node.nodeType === Node.ELEMENT_NODE) {
+    var type = node.getAttribute('is') || node.localName;
+    var definition = scope.registry[type];
+    if (definition) {
+      logFlags.dom && console.group('upgrade:', node.localName);
+      scope.upgrade(node);
+      logFlags.dom && console.groupEnd();
+      return true;
+    }
+  }
+}
+
+function insertedNode(node) {
+  inserted(node);
+  if (inDocument(node)) {
+    forSubtree(node, function(e) {
+      inserted(e);
+    });
+  }
+}
+
+
+// TODO(sorvell): on platforms without MutationObserver, mutations may not be 
+// reliable and therefore attached/detached are not reliable.
+// To make these callbacks less likely to fail, we defer all inserts and removes
+// to give a chance for elements to be inserted into dom. 
+// This ensures attachedCallback fires for elements that are created and 
+// immediately added to dom.
+var hasPolyfillMutations = (!window.MutationObserver ||
+    (window.MutationObserver === window.JsMutationObserver));
+scope.hasPolyfillMutations = hasPolyfillMutations;
+
+var isPendingMutations = false;
+var pendingMutations = [];
+function deferMutation(fn) {
+  pendingMutations.push(fn);
+  if (!isPendingMutations) {
+    isPendingMutations = true;
+    var async = (window.Platform && window.Platform.endOfMicrotask) ||
+        setTimeout;
+    async(takeMutations);
+  }
+}
+
+function takeMutations() {
+  isPendingMutations = false;
+  var $p = pendingMutations;
+  for (var i=0, l=$p.length, p; (i<l) && (p=$p[i]); i++) {
+    p();
+  }
+  pendingMutations = [];
+}
+
+function inserted(element) {
+  if (hasPolyfillMutations) {
+    deferMutation(function() {
+      _inserted(element);
+    });
+  } else {
+    _inserted(element);
+  }
+}
+
+// TODO(sjmiles): if there are descents into trees that can never have inDocument(*) true, fix this
+function _inserted(element) {
+  // TODO(sjmiles): it's possible we were inserted and removed in the space
+  // of one microtask, in which case we won't be 'inDocument' here
+  // But there are other cases where we are testing for inserted without
+  // specific knowledge of mutations, and must test 'inDocument' to determine
+  // whether to call inserted
+  // If we can factor these cases into separate code paths we can have
+  // better diagnostics.
+  // TODO(sjmiles): when logging, do work on all custom elements so we can
+  // track behavior even when callbacks not defined
+  //console.log('inserted: ', element.localName);
+  if (element.attachedCallback || element.detachedCallback || (element.__upgraded__ && logFlags.dom)) {
+    logFlags.dom && console.group('inserted:', element.localName);
+    if (inDocument(element)) {
+      element.__inserted = (element.__inserted || 0) + 1;
+      // if we are in a 'removed' state, bluntly adjust to an 'inserted' state
+      if (element.__inserted < 1) {
+        element.__inserted = 1;
+      }
+      // if we are 'over inserted', squelch the callback
+      if (element.__inserted > 1) {
+        logFlags.dom && console.warn('inserted:', element.localName,
+          'insert/remove count:', element.__inserted)
+      } else if (element.attachedCallback) {
+        logFlags.dom && console.log('inserted:', element.localName);
+        element.attachedCallback();
+      }
+    }
+    logFlags.dom && console.groupEnd();
+  }
+}
+
+function removedNode(node) {
+  removed(node);
+  forSubtree(node, function(e) {
+    removed(e);
+  });
+}
+
+function removed(element) {
+  if (hasPolyfillMutations) {
+    deferMutation(function() {
+      _removed(element);
+    });
+  } else {
+    _removed(element);
+  }
+}
+
+function _removed(element) {
+  // TODO(sjmiles): temporary: do work on all custom elements so we can track
+  // behavior even when callbacks not defined
+  if (element.attachedCallback || element.detachedCallback || (element.__upgraded__ && logFlags.dom)) {
+    logFlags.dom && console.group('removed:', element.localName);
+    if (!inDocument(element)) {
+      element.__inserted = (element.__inserted || 0) - 1;
+      // if we are in a 'inserted' state, bluntly adjust to an 'removed' state
+      if (element.__inserted > 0) {
+        element.__inserted = 0;
+      }
+      // if we are 'over removed', squelch the callback
+      if (element.__inserted < 0) {
+        logFlags.dom && console.warn('removed:', element.localName,
+            'insert/remove count:', element.__inserted)
+      } else if (element.detachedCallback) {
+        element.detachedCallback();
+      }
+    }
+    logFlags.dom && console.groupEnd();
+  }
+}
+
+// SD polyfill intrustion due mainly to the fact that 'document'
+// is not entirely wrapped
+function wrapIfNeeded(node) {
+  return window.ShadowDOMPolyfill ? ShadowDOMPolyfill.wrapIfNeeded(node)
+      : node;
+}
+
+function inDocument(element) {
+  var p = element;
+  var doc = wrapIfNeeded(document);
+  while (p) {
+    if (p == doc) {
+      return true;
+    }
+    p = p.parentNode || p.host;
+  }
+}
+
+function watchShadow(node) {
+  if (node.shadowRoot && !node.shadowRoot.__watched) {
+    logFlags.dom && console.log('watching shadow-root for: ', node.localName);
+    // watch all unwatched roots...
+    var root = node.shadowRoot;
+    while (root) {
+      watchRoot(root);
+      root = root.olderShadowRoot;
+    }
+  }
+}
+
+function watchRoot(root) {
+  if (!root.__watched) {
+    observe(root);
+    root.__watched = true;
+  }
+}
+
+function handler(mutations) {
+  //
+  if (logFlags.dom) {
+    var mx = mutations[0];
+    if (mx && mx.type === 'childList' && mx.addedNodes) {
+        if (mx.addedNodes) {
+          var d = mx.addedNodes[0];
+          while (d && d !== document && !d.host) {
+            d = d.parentNode;
+          }
+          var u = d && (d.URL || d._URL || (d.host && d.host.localName)) || '';
+          u = u.split('/?').shift().split('/').pop();
+        }
+    }
+    console.group('mutations (%d) [%s]', mutations.length, u || '');
+  }
+  //
+  mutations.forEach(function(mx) {
+    //logFlags.dom && console.group('mutation');
+    if (mx.type === 'childList') {
+      forEach(mx.addedNodes, function(n) {
+        //logFlags.dom && console.log(n.localName);
+        if (!n.localName) {
+          return;
+        }
+        // nodes added may need lifecycle management
+        addedNode(n);
+      });
+      // removed nodes may need lifecycle management
+      forEach(mx.removedNodes, function(n) {
+        //logFlags.dom && console.log(n.localName);
+        if (!n.localName) {
+          return;
+        }
+        removedNode(n);
+      });
+    }
+    //logFlags.dom && console.groupEnd();
+  });
+  logFlags.dom && console.groupEnd();
+};
+
+var observer = new MutationObserver(handler);
+
+function takeRecords() {
+  // TODO(sjmiles): ask Raf why we have to call handler ourselves
+  handler(observer.takeRecords());
+  takeMutations();
+}
+
+var forEach = Array.prototype.forEach.call.bind(Array.prototype.forEach);
+
+function observe(inRoot) {
+  observer.observe(inRoot, {childList: true, subtree: true});
+}
+
+function observeDocument(doc) {
+  observe(doc);
+}
+
+function upgradeDocument(doc) {
+  logFlags.dom && console.group('upgradeDocument: ', (doc.baseURI).split('/').pop());
+  addedNode(doc);
+  logFlags.dom && console.groupEnd();
+}
+
+function upgradeDocumentTree(doc) {
+  doc = wrapIfNeeded(doc);
+  upgradeDocument(doc);
+  //console.log('upgradeDocumentTree: ', (doc.baseURI).split('/').pop());
+  // upgrade contained imported documents
+  var imports = doc.querySelectorAll('link[rel=' + IMPORT_LINK_TYPE + ']');
+  for (var i=0, l=imports.length, n; (i<l) && (n=imports[i]); i++) {
+    if (n.import && n.import.__parsed) {
+      upgradeDocumentTree(n.import);
+    }
+  }
+}
+
+// exports
+scope.IMPORT_LINK_TYPE = IMPORT_LINK_TYPE;
+scope.watchShadow = watchShadow;
+scope.upgradeDocumentTree = upgradeDocumentTree;
+scope.upgradeAll = addedNode;
+scope.upgradeSubtree = addedSubtree;
+
+scope.observeDocument = observeDocument;
+scope.upgradeDocument = upgradeDocument;
+
+scope.takeRecords = takeRecords;
+
+})(window.CustomElements);
+
+/**
+ * Implements `document.register`
+ * @module CustomElements
+*/
+
+/**
+ * Polyfilled extensions to the `document` object.
+ * @class Document
+*/
+
+(function(scope) {
+
+// imports
+
+if (!scope) {
+  scope = window.CustomElements = {flags:{}};
+}
+var flags = scope.flags;
+
+// native document.registerElement?
+
+var hasNative = Boolean(document.registerElement);
+// TODO(sorvell): See https://github.com/Polymer/polymer/issues/399
+// we'll address this by defaulting to CE polyfill in the presence of the SD
+// polyfill. This will avoid spamming excess attached/detached callbacks.
+// If there is a compelling need to run CE native with SD polyfill, 
+// we'll need to fix this issue.
+var useNative = !flags.register && hasNative && !window.ShadowDOMPolyfill;
+
+if (useNative) {
+
+  // stub
+  var nop = function() {};
+
+  // exports
+  scope.registry = {};
+  scope.upgradeElement = nop;
+
+  scope.watchShadow = nop;
+  scope.upgrade = nop;
+  scope.upgradeAll = nop;
+  scope.upgradeSubtree = nop;
+  scope.observeDocument = nop;
+  scope.upgradeDocument = nop;
+  scope.takeRecords = nop;
+
+} else {
+
+  /**
+   * Registers a custom tag name with the document.
+   *
+   * When a registered element is created, a `readyCallback` method is called
+   * in the scope of the element. The `readyCallback` method can be specified on
+   * either `options.prototype` or `options.lifecycle` with the latter taking
+   * precedence.
+   *
+   * @method register
+   * @param {String} name The tag name to register. Must include a dash ('-'),
+   *    for example 'x-component'.
+   * @param {Object} options
+   *    @param {String} [options.extends]
+   *      (_off spec_) Tag name of an element to extend (or blank for a new
+   *      element). This parameter is not part of the specification, but instead
+   *      is a hint for the polyfill because the extendee is difficult to infer.
+   *      Remember that the input prototype must chain to the extended element's
+   *      prototype (or HTMLElement.prototype) regardless of the value of
+   *      `extends`.
+   *    @param {Object} options.prototype The prototype to use for the new
+   *      element. The prototype must inherit from HTMLElement.
+   *    @param {Object} [options.lifecycle]
+   *      Callbacks that fire at important phases in the life of the custom
+   *      element.
+   *
+   * @example
+   *      FancyButton = document.registerElement("fancy-button", {
+   *        extends: 'button',
+   *        prototype: Object.create(HTMLButtonElement.prototype, {
+   *          readyCallback: {
+   *            value: function() {
+   *              console.log("a fancy-button was created",
+   *            }
+   *          }
+   *        })
+   *      });
+   * @return {Function} Constructor for the newly registered type.
+   */
+  function register(name, options) {
+    //console.warn('document.registerElement("' + name + '", ', options, ')');
+    // construct a defintion out of options
+    // TODO(sjmiles): probably should clone options instead of mutating it
+    var definition = options || {};
+    if (!name) {
+      // TODO(sjmiles): replace with more appropriate error (EricB can probably
+      // offer guidance)
+      throw new Error('document.registerElement: first argument `name` must not be empty');
+    }
+    if (name.indexOf('-') < 0) {
+      // TODO(sjmiles): replace with more appropriate error (EricB can probably
+      // offer guidance)
+      throw new Error('document.registerElement: first argument (\'name\') must contain a dash (\'-\'). Argument provided was \'' + String(name) + '\'.');
+    }
+    // elements may only be registered once
+    if (getRegisteredDefinition(name)) {
+      throw new Error('DuplicateDefinitionError: a type with name \'' + String(name) + '\' is already registered');
+    }
+    // must have a prototype, default to an extension of HTMLElement
+    // TODO(sjmiles): probably should throw if no prototype, check spec
+    if (!definition.prototype) {
+      // TODO(sjmiles): replace with more appropriate error (EricB can probably
+      // offer guidance)
+      throw new Error('Options missing required prototype property');
+    }
+    // record name
+    definition.__name = name.toLowerCase();
+    // ensure a lifecycle object so we don't have to null test it
+    definition.lifecycle = definition.lifecycle || {};
+    // build a list of ancestral custom elements (for native base detection)
+    // TODO(sjmiles): we used to need to store this, but current code only
+    // uses it in 'resolveTagName': it should probably be inlined
+    definition.ancestry = ancestry(definition.extends);
+    // extensions of native specializations of HTMLElement require localName
+    // to remain native, and use secondary 'is' specifier for extension type
+    resolveTagName(definition);
+    // some platforms require modifications to the user-supplied prototype
+    // chain
+    resolvePrototypeChain(definition);
+    // overrides to implement attributeChanged callback
+    overrideAttributeApi(definition.prototype);
+    // 7.1.5: Register the DEFINITION with DOCUMENT
+    registerDefinition(definition.__name, definition);
+    // 7.1.7. Run custom element constructor generation algorithm with PROTOTYPE
+    // 7.1.8. Return the output of the previous step.
+    definition.ctor = generateConstructor(definition);
+    definition.ctor.prototype = definition.prototype;
+    // force our .constructor to be our actual constructor
+    definition.prototype.constructor = definition.ctor;
+    // if initial parsing is complete
+    if (scope.ready || scope.performedInitialDocumentUpgrade) {
+      // upgrade any pre-existing nodes of this type
+      scope.upgradeDocumentTree(document);
+    }
+    return definition.ctor;
+  }
+
+  function ancestry(extnds) {
+    var extendee = getRegisteredDefinition(extnds);
+    if (extendee) {
+      return ancestry(extendee.extends).concat([extendee]);
+    }
+    return [];
+  }
+
+  function resolveTagName(definition) {
+    // if we are explicitly extending something, that thing is our
+    // baseTag, unless it represents a custom component
+    var baseTag = definition.extends;
+    // if our ancestry includes custom components, we only have a
+    // baseTag if one of them does
+    for (var i=0, a; (a=definition.ancestry[i]); i++) {
+      baseTag = a.is && a.tag;
+    }
+    // our tag is our baseTag, if it exists, and otherwise just our name
+    definition.tag = baseTag || definition.__name;
+    if (baseTag) {
+      // if there is a base tag, use secondary 'is' specifier
+      definition.is = definition.__name;
+    }
+  }
+
+  function resolvePrototypeChain(definition) {
+    // if we don't support __proto__ we need to locate the native level
+    // prototype for precise mixing in
+    if (!Object.__proto__) {
+      // default prototype
+      var nativePrototype = HTMLElement.prototype;
+      // work out prototype when using type-extension
+      if (definition.is) {
+        var inst = document.createElement(definition.tag);
+        nativePrototype = Object.getPrototypeOf(inst);
+      }
+      // ensure __proto__ reference is installed at each point on the prototype
+      // chain.
+      // NOTE: On platforms without __proto__, a mixin strategy is used instead
+      // of prototype swizzling. In this case, this generated __proto__ provides
+      // limited support for prototype traversal.
+      var proto = definition.prototype, ancestor;
+      while (proto && (proto !== nativePrototype)) {
+        var ancestor = Object.getPrototypeOf(proto);
+        proto.__proto__ = ancestor;
+        proto = ancestor;
+      }
+    }
+    // cache this in case of mixin
+    definition.native = nativePrototype;
+  }
+
+  // SECTION 4
+
+  function instantiate(definition) {
+    // 4.a.1. Create a new object that implements PROTOTYPE
+    // 4.a.2. Let ELEMENT by this new object
+    //
+    // the custom element instantiation algorithm must also ensure that the
+    // output is a valid DOM element with the proper wrapper in place.
+    //
+    return upgrade(domCreateElement(definition.tag), definition);
+  }
+
+  function upgrade(element, definition) {
+    // some definitions specify an 'is' attribute
+    if (definition.is) {
+      element.setAttribute('is', definition.is);
+    }
+    // remove 'unresolved' attr, which is a standin for :unresolved.
+    element.removeAttribute('unresolved');
+    // make 'element' implement definition.prototype
+    implement(element, definition);
+    // flag as upgraded
+    element.__upgraded__ = true;
+    // there should never be a shadow root on element at this point
+    // we require child nodes be upgraded before `created`
+    scope.upgradeSubtree(element);
+    // lifecycle management
+    created(element);
+    // OUTPUT
+    return element;
+  }
+
+  function implement(element, definition) {
+    // prototype swizzling is best
+    if (Object.__proto__) {
+      element.__proto__ = definition.prototype;
+    } else {
+      // where above we can re-acquire inPrototype via
+      // getPrototypeOf(Element), we cannot do so when
+      // we use mixin, so we install a magic reference
+      customMixin(element, definition.prototype, definition.native);
+
+      // Dart note: make sure we pick up the right constructor.
+      // dart2js depends on this for dart:mirrors caching to work.
+      // See tests/html/custom/mirrors_test.dart
+      element.constructor = definition.prototype.constructor;
+      element.__proto__ = definition.prototype;
+    }
+  }
+
+  function customMixin(inTarget, inSrc, inNative) {
+    // TODO(sjmiles): 'used' allows us to only copy the 'youngest' version of
+    // any property. This set should be precalculated. We also need to
+    // consider this for supporting 'super'.
+    var used = {};
+    // start with inSrc
+    var p = inSrc;
+    // sometimes the default is HTMLUnknownElement.prototype instead of
+    // HTMLElement.prototype, so we add a test
+    // the idea is to avoid mixing in native prototypes, so adding
+    // the second test is WLOG
+    while (p !== inNative && p !== HTMLUnknownElement.prototype) {
+      var keys = Object.getOwnPropertyNames(p);
+      for (var i=0, k; k=keys[i]; i++) {
+        if (!used[k]) {
+          Object.defineProperty(inTarget, k,
+              Object.getOwnPropertyDescriptor(p, k));
+          used[k] = 1;
+        }
+      }
+      p = Object.getPrototypeOf(p);
+    }
+  }
+
+  function created(element) {
+    // invoke createdCallback
+    if (element.createdCallback) {
+      element.createdCallback();
+    }
+  }
+
+  // attribute watching
+
+  function overrideAttributeApi(prototype) {
+    // overrides to implement callbacks
+    // TODO(sjmiles): should support access via .attributes NamedNodeMap
+    // TODO(sjmiles): preserves user defined overrides, if any
+    if (prototype.setAttribute._polyfilled) {
+      return;
+    }
+    var setAttribute = prototype.setAttribute;
+    prototype.setAttribute = function(name, value) {
+      changeAttribute.call(this, name, value, setAttribute);
+    }
+    var removeAttribute = prototype.removeAttribute;
+    prototype.removeAttribute = function(name) {
+      changeAttribute.call(this, name, null, removeAttribute);
+    }
+    prototype.setAttribute._polyfilled = true;
+  }
+
+  // https://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/custom/
+  // index.html#dfn-attribute-changed-callback
+  function changeAttribute(name, value, operation) {
+    var oldValue = this.getAttribute(name);
+    operation.apply(this, arguments);
+    var newValue = this.getAttribute(name);
+    if (this.attributeChangedCallback
+        && (newValue !== oldValue)) {
+      this.attributeChangedCallback(name, oldValue, newValue);
+    }
+  }
+
+  // element registry (maps tag names to definitions)
+
+  var registry = {};
+
+  function getRegisteredDefinition(name) {
+    if (name) {
+      return registry[name.toLowerCase()];
+    }
+  }
+
+  function registerDefinition(name, definition) {
+    if (registry[name]) {
+      throw new Error('a type with that name is already registered.');
+    }
+    registry[name] = definition;
+  }
+
+  function generateConstructor(definition) {
+    return function() {
+      return instantiate(definition);
+    };
+  }
+
+  function createElement(tag, typeExtension) {
+    // TODO(sjmiles): ignore 'tag' when using 'typeExtension', we could
+    // error check it, or perhaps there should only ever be one argument
+    var definition = getRegisteredDefinition(typeExtension || tag);
+    if (definition) {
+      if (tag == definition.tag && typeExtension == definition.is) {
+        return new definition.ctor();
+      }
+      // Handle empty string for type extension.
+      if (!typeExtension && !definition.is) {
+        return new definition.ctor();
+      }
+    }
+
+    if (typeExtension) {
+      var element = createElement(tag);
+      element.setAttribute('is', typeExtension);
+      return element;
+    }
+    var element = domCreateElement(tag);
+    // Custom tags should be HTMLElements even if not upgraded.
+    if (tag.indexOf('-') >= 0) {
+      implement(element, HTMLElement);
+    }
+    return element;
+  }
+
+  function upgradeElement(element) {
+    if (!element.__upgraded__ && (element.nodeType === Node.ELEMENT_NODE)) {
+      var is = element.getAttribute('is');
+      var definition = registry[is || element.localName];
+      if (definition) {
+        if (is && definition.tag == element.localName) {
+          return upgrade(element, definition);
+        } else if (!is && !definition.extends) {
+          return upgrade(element, definition);
+        }
+      }
+    }
+  }
+
+  function cloneNode(deep) {
+    // call original clone
+    var n = domCloneNode.call(this, deep);
+    // upgrade the element and subtree
+    scope.upgradeAll(n);
+    // return the clone
+    return n;
+  }
+  // capture native createElement before we override it
+
+  var domCreateElement = document.createElement.bind(document);
+
+  // capture native cloneNode before we override it
+
+  var domCloneNode = Node.prototype.cloneNode;
+
+  // exports
+
+  document.registerElement = register;
+  document.createElement = createElement; // override
+  Node.prototype.cloneNode = cloneNode; // override
+
+  scope.registry = registry;
+
+  /**
+   * Upgrade an element to a custom element. Upgrading an element
+   * causes the custom prototype to be applied, an `is` attribute
+   * to be attached (as needed), and invocation of the `readyCallback`.
+   * `upgrade` does nothing if the element is already upgraded, or
+   * if it matches no registered custom tag name.
+   *
+   * @method ugprade
+   * @param {Element} element The element to upgrade.
+   * @return {Element} The upgraded element.
+   */
+  scope.upgrade = upgradeElement;
+}
+
+// bc
+document.register = document.registerElement;
+
+scope.hasNative = hasNative;
+scope.useNative = useNative;
+
+})(window.CustomElements);
+
+(function(scope) {
+
+// import
+
+var IMPORT_LINK_TYPE = scope.IMPORT_LINK_TYPE;
+
+// highlander object for parsing a document tree
+
+var parser = {
+  selectors: [
+    'link[rel=' + IMPORT_LINK_TYPE + ']'
+  ],
+  map: {
+    link: 'parseLink'
+  },
+  parse: function(inDocument) {
+    if (!inDocument.__parsed) {
+      // only parse once
+      inDocument.__parsed = true;
+      // all parsable elements in inDocument (depth-first pre-order traversal)
+      var elts = inDocument.querySelectorAll(parser.selectors);
+      // for each parsable node type, call the mapped parsing method
+      forEach(elts, function(e) {
+        parser[parser.map[e.localName]](e);
+      });
+      // upgrade all upgradeable static elements, anything dynamically
+      // created should be caught by observer
+      CustomElements.upgradeDocument(inDocument);
+      // observe document for dom changes
+      CustomElements.observeDocument(inDocument);
+    }
+  },
+  parseLink: function(linkElt) {
+    // imports
+    if (isDocumentLink(linkElt)) {
+      this.parseImport(linkElt);
+    }
+  },
+  parseImport: function(linkElt) {
+    if (linkElt.import) {
+      parser.parse(linkElt.import);
+    }
+  }
+};
+
+function isDocumentLink(inElt) {
+  return (inElt.localName === 'link'
+      && inElt.getAttribute('rel') === IMPORT_LINK_TYPE);
+}
+
+var forEach = Array.prototype.forEach.call.bind(Array.prototype.forEach);
+
+// exports
+
+scope.parser = parser;
+scope.IMPORT_LINK_TYPE = IMPORT_LINK_TYPE;
+
+})(window.CustomElements);
+(function(scope){
+
+// bootstrap parsing
+function bootstrap() {
+  // parse document
+  CustomElements.parser.parse(document);
+  // one more pass before register is 'live'
+  CustomElements.upgradeDocument(document);
+  CustomElements.performedInitialDocumentUpgrade = true;
+  // choose async
+  var async = window.Platform && Platform.endOfMicrotask ?
+    Platform.endOfMicrotask :
+    setTimeout;
+  async(function() {
+    // set internal 'ready' flag, now document.registerElement will trigger 
+    // synchronous upgrades
+    CustomElements.ready = true;
+    // capture blunt profiling data
+    CustomElements.readyTime = Date.now();
+    if (window.HTMLImports) {
+      CustomElements.elapsed = CustomElements.readyTime - HTMLImports.readyTime;
+    }
+    // notify the system that we are bootstrapped
+    document.dispatchEvent(
+      new CustomEvent('WebComponentsReady', {bubbles: true})
+    );
+  });
+}
+
+// CustomEvent shim for IE
+if (typeof window.CustomEvent !== 'function') {
+  window.CustomEvent = function(inType) {
+    var e = document.createEvent('HTMLEvents');
+    e.initEvent(inType, true, true);
+    return e;
+  };
+}
+
+// When loading at readyState complete time (or via flag), boot custom elements
+// immediately.
+// If relevant, HTMLImports must already be loaded.
+if (document.readyState === 'complete' || scope.flags.eager) {
+  bootstrap();
+// When loading at readyState interactive time, bootstrap only if HTMLImports
+// are not pending. Also avoid IE as the semantics of this state are unreliable.
+} else if (document.readyState === 'interactive' && !window.attachEvent &&
+    (!window.HTMLImports || window.HTMLImports.ready)) {
+  bootstrap();
+// When loading at other readyStates, wait for the appropriate DOM event to
+// bootstrap.
+} else {
+  var loadEvent = window.HTMLImports && !HTMLImports.ready
+      ? 'HTMLImportsLoaded'
+      : document.readyState == 'loading' ? 'DOMContentLoaded' : 'load';
+  window.addEventListener(loadEvent, bootstrap);
+}
+
+})(window.CustomElements);
+
+(function() {
+// Patch to allow custom element and shadow dom to work together, from:
+// https://github.com/Polymer/platform-dev/blob/60ece8c323c5d9325cbfdfd6e8cd180d4f38a3bc/src/patches-shadowdom-polyfill.js
+// include .host reference
+if (HTMLElement.prototype.createShadowRoot) {
+  var originalCreateShadowRoot = HTMLElement.prototype.createShadowRoot;
+  HTMLElement.prototype.createShadowRoot = function() {
+    var root = originalCreateShadowRoot.call(this);
+    root.host = this;
+    CustomElements.watchShadow(this);
+    return root;
+  }
+}
+
+
+// Patch to allow custom elements and shadow dom to work together, from:
+// https://github.com/Polymer/platform-dev/blob/2bb9c56d90f9ac19c2e65cdad368668aff514f14/src/patches-custom-elements.js
+if (window.ShadowDOMPolyfill) {
+
+  // ensure wrapped inputs for these functions
+  var fns = ['upgradeAll', 'upgradeSubtree', 'observeDocument',
+      'upgradeDocument'];
+
+  // cache originals
+  var original = {};
+  fns.forEach(function(fn) {
+    original[fn] = CustomElements[fn];
+  });
+
+  // override
+  fns.forEach(function(fn) {
+    CustomElements[fn] = function(inNode) {
+      return original[fn](window.ShadowDOMPolyfill.wrapIfNeeded(inNode));
+    };
+  });
+
+}
+
+// Patch to make importNode work.
+// https://github.com/Polymer/platform-dev/blob/64a92f273462f04a84abbe2f054294f2b62dbcd6/src/patches-mdv.js
+if (window.CustomElements && !CustomElements.useNative) {
+  var originalImportNode = Document.prototype.importNode;
+  Document.prototype.importNode = function(node, deep) {
+    var imported = originalImportNode.call(this, node, deep);
+    CustomElements.upgradeAll(imported);
+    return imported;
+  }
+}
+
+})();