update elements and fix some bugs

lib/src/iron-iconset-svg/iron-iconset-svg.html

Index: lib/src/iron-iconset-svg/iron-iconset-svg.html
diff --git a/lib/src/iron-iconset-svg/iron-iconset-svg.html b/lib/src/iron-iconset-svg/iron-iconset-svg.html
index 3cebc2ce1d3283ff6e61dc514cd7699706de4de4..da20aee4ffba2b8eb65d70e27afa9496d488c7fc 100644
--- a/lib/src/iron-iconset-svg/iron-iconset-svg.html
+++ b/lib/src/iron-iconset-svg/iron-iconset-svg.html
@@ -18,9 +18,9 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
    * `iron-iconset-svg` element. Multiple icons should be given distinct id's.
    *
    * Using svg elements to create icons has a few advantages over traditional
-   * bitmap graphics like jpg or png. Icons that use svg are vector based so they
-   * are resolution independent and should look good on any device. They are
-   * stylable via css. Icons can be themed, colorized, and even animated.
+   * bitmap graphics like jpg or png. Icons that use svg are vector based so
+   * they are resolution independent and should look good on any device. They
+   * are stylable via css. Icons can be themed, colorized, and even animated.
    *
    * Example:
    *
@@ -45,18 +45,15 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
    *
    * @element iron-iconset-svg
    * @demo demo/index.html
+   * @implements {Polymer.Iconset}
    */
   Polymer({
-
     is: 'iron-iconset-svg',
 
     properties: {
 
       /**
        * The name of the iconset.
-       *
-       * @attribute name
-       * @type string
        */
       name: {
         type: String,
@@ -65,10 +62,6 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
 
       /**
        * The size of an individual icon. Note that icons must be square.
-       *
-       * @attribute iconSize
-       * @type number
-       * @default 24
        */
       size: {
         type: Number,
@@ -76,6 +69,10 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
       }
 
     },
+    
+    attached: function() {
+      this.style.display = 'none';
+    },
 
     /**
      * Construct an array of all icon names in this iconset.
@@ -98,7 +95,7 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
      * @method applyIcon
      * @param {Element} element Element to which the icon is applied.
      * @param {string} iconName Name of the icon to apply.
-     * @return {Element} The svg element which renders the icon.
+     * @return {?Element} The svg element which renders the icon.
      */
     applyIcon: function(element, iconName) {
       // insert svg element into shadow root, if it exists
@@ -136,6 +133,9 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
      */
     _nameChanged: function() {
       new Polymer.IronMeta({type: 'iconset', key: this.name, value: this});
+      this.async(function() {
+        this.fire('iron-iconset-added', this, {node: window});
+      });
     },
 
     /**
@@ -176,13 +176,15 @@ subject to an additional IP rights grant found at http://polymer.github.io/PATEN
      */
     _prepareSvgClone: function(sourceSvg, size) {
       if (sourceSvg) {
-        var svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
-        svg.setAttribute('viewBox', ['0', '0', size, size].join(' '));
+        var content = sourceSvg.cloneNode(true),
+            svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg'),
+            viewBox = content.getAttribute('viewBox') || '0 0 ' + size + ' ' + size;
+        svg.setAttribute('viewBox', viewBox);
         svg.setAttribute('preserveAspectRatio', 'xMidYMid meet');
         // TODO(dfreedm): `pointer-events: none` works around https://crbug.com/370136
         // TODO(sjmiles): inline style may not be ideal, but avoids requiring a shadow-root
         svg.style.cssText = 'pointer-events: none; display: block; width: 100%; height: 100%;';
-        svg.appendChild(sourceSvg.cloneNode(true)).removeAttribute('id');
+        svg.appendChild(content).removeAttribute('id');
         return svg;
       }
       return null;