fixes #7

core-header-panel.html

@@ -87,6 +87,14 @@
 <script>
 
   Polymer('core-header-panel', {
+
+    /**
+     * Fired when the content has been scrolled.  `details.target` returns
+     * the scrollable element which you can use to access scroll info such as
+     * `scrollTop`.
+     *
+     * @event scroll
+     */
 
     publish: {
       /**
@@ -168,6 +176,14 @@
       return this.$.headerContent.getDistributedNodes()[0];
     },
 
+    /**
+     * Returns the scrollable element.
+     */
+    get scroller() {
+      return this.mode === 'scroll' ? 
+          this.$.outerContainer : this.$.mainContainer;
+    },
+
     scroll: function() {
       var shadowMode = {'waterfall': 1, 'waterfall-tall': 1};
       var noShadow = {'seamed': 1, 'cover': 1, 'scroll': 1};
@@ -189,6 +205,8 @@
 
         header.classList.toggle('animate', tallMode[this.mode]);
       }
+
+      this.fire('scroll', {target: this.scroller}, this, false);
     }
 
   });