Import Polymer 0.8 and several key elements.

third_party/polymer/v0_8/components/polymer/src/lib/collection.html

Index: third_party/polymer/v0_8/components/polymer/src/lib/collection.html
diff --git a/third_party/polymer/v0_8/components/polymer/src/lib/collection.html b/third_party/polymer/v0_8/components/polymer/src/lib/collection.html
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+<!--
+@license
+Copyright (c) 2014 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+-->
+
+<link rel="import" href="array-observe.html">
+<link rel="import" href="debounce.html">
+
+<script>
+
+  Polymer._collections = new WeakMap();
+
+  Polymer.Collection = function(userArray, noObserve) {
+    Polymer._collections.set(userArray, this);
+    this.userArray = userArray;
+    this.store = userArray.slice();
+    this.callbacks = [];
+    this.debounce = null;
+    this.map = null;
+    this.added = [];
+    this.removed = [];
+    if (!noObserve) {
+      Polymer.ArrayObserve.observe(userArray, this.applySplices.bind(this));
+      this.initMap();
+    }
+  };
+
+  Polymer.Collection.prototype = {
+    constructor: Polymer.Collection,
+
+    initMap: function() {
+      var map = this.map = new WeakMap();
+      var s = this.store;
+      var u = this.userArray;
+      for (var i=0; i<s.length; i++) {
+        var v = s[i];
+        if (v) {
+          switch (typeof v) {
+            case 'string':
+              v = s[i] = u[i]= new String(v);
+              break;
+            case 'number':
+              v = s[i] = u[i]= new Number(v);
+              break;          
+            case 'boolean':
+              v = s[i] = u[i]= new Boolean(v);
+              break;          
+          }
+        map.set(v, i);
+        }
+      }
+    },
+
+    add: function(item, squelch) {
+      var key = this.store.push(item) - 1;
+      if (item != null && this.map) {
+        this.map.set(item, key);
+      }
+      if (!squelch) {
+        this.added.push(key);
+        this.debounce = Polymer.Debounce(this.debounce, this.notify.bind(this));
+      }
+      return key;
+    },
+
+    removeKey: function(key) {
+      if (this.map) {
+        this.map.delete(this.store[key]);
+      }
+      delete this.store[key];
+      this.removed.push(key);
+      this.debounce = Polymer.Debounce(this.debounce, this.notify.bind(this));
+    },
+
+    remove: function(item, squelch) {
+      var key = this.getKey(item);
+      if (item != null && this.map) {
+        this.map.delete(item);
+      }
+      delete this.store[key];
+      if (!squelch) {
+        this.removed.push(key);
+        this.debounce = Polymer.Debounce(this.debounce, this.notify.bind(this));
+      }
+      return key;
+    },
+
+    notify: function(splices) {
+      if (!splices) {
+        splices = [{
+          added: this.added,
+          removed: this.removed
+        }];
+        this.added = [];
+        this.removed = [];
+      }
+      this.callbacks.forEach(function(cb) {
+        cb(splices);
+      }, this);
+    },
+
+    observe: function(callback) {
+      this.callbacks.push(callback);
+    },
+
+    unobserve: function(callback) {
+      this.callbacks.splice(this.callbacks.indexOf(callback), 1);
+    },
+
+    getKey: function(item) {
+      if (item != null && this.map) {
+        return this.map.get(item);
+      } else {
+        return this.store.indexOf(item);      
+      }
+    },
+
+    getKeys: function() {
+      return Object.keys(this.store);
+    },
+
+    setItem: function(key, value) {
+      this.store[key] = value;
+    },
+
+    getItem: function(key) {
+      return this.store[key];
+    },
+
+    getItems: function() {
+      var items = [], store = this.store;
+      for (var key in store) {
+        items.push(store[key]);
+      }
+      return items;
+    },
+
+    applySplices: function(splices) {
+      var map = this.map;
+      var keySplices = [];
+      for (var i=0; i<splices.length; i++) {
+        var j, o, key, s = splices[i];
+        // Removed keys
+        var removed = [];
+        for (j=0; j<s.removed.length; j++) {
+          o = s.removed[j];
+          key = this.remove(o, true);
+          removed.push(key);
+        }
+        // Added keys
+        var added = [];
+        for (j=0; j<s.addedCount; j++) {
+          o = this.userArray[s.index + j];
+          key = this.add(o, true);
+          added.push(key);
+        }
+        // Record splice
+        keySplices.push({
+          index: s.index,
+          removed: removed,
+          added: added
+        });
+      }
+      this.notify(keySplices);
+    }
+
+  };
+
+  Polymer.Collection.get = function(userArray, noObserve) {
+    return Polymer._collections.get(userArray) 
+      || new Polymer.Collection(userArray, noObserve);
+  };
+
+</script>