update elements and fix some bugs

lib/src/google-map/google-map-point.html

+<!-- Copyright (c) 2015 Google Inc. All rights reserved. -->
+
+<link rel="import" href="../polymer/polymer.html">
+<link rel="import" href="../google-apis/google-maps-api.html">
+
+<!--
+The `google-map-point` element represents a point on a map. It's used as a child of other
+google-map-* elements.
+
+<b>Example</b>—points defining a semi-translucent blue triangle:
+
+    <google-map latitude="37.77493" longitude="-122.41942">
+      <google-map-poly closed fill-color="blue" fill-opacity=".5">
+        <google-map-point latitude="36.77493" longitude="-121.41942"></google-map-point>
+        <google-map-point latitude="38.77493" longitude="-122.41942"></google-map-point>
+        <google-map-point latitude="36.77493" longitude="-123.41942"></google-map-point>
+      </google-map-poly>
+    </google-map>
+-->
+<script>
+  Polymer({
+    is: 'google-map-point',
+
+    hostAttributes: {hidden: true},
+
+    properties: {
+      /**
+       * The point's longitude coordinate.
+       */
+       longitude: {
+         type: Number,
+         value: null
+       },
+
+      /**
+       * The point's latitude coordinate.
+       */
+       latitude: {
+         type: Number,
+         value: null
+       }
+    },
+
+    /**
+     * Returns the point as a Google Maps LatLng object.
+     *
+     * @return {google.maps.LatLnt} The LatLng object.
+     */
+    getPosition: function() {
+      return new google.maps.LatLng(this.latitude, this.longitude);
+    }
+  });
+</script>