From 0a08aae0548c9ddee2447df8819af12cb1d62827 Mon Sep 17 00:00:00 2001
From: Pavel Makhov <pavel.makhov@cern.ch>
Date: Mon, 2 May 2016 13:45:35 +0200
Subject: [PATCH] fix issue when no src attr is provided

---
 demo/index.html  | 12 +-----------
 pdf-element.html | 19 +++++++++----------
 2 files changed, 10 insertions(+), 21 deletions(-)

diff --git a/demo/index.html b/demo/index.html
index 821d18d..0d1041a 100644
--- a/demo/index.html
+++ b/demo/index.html
@@ -57,17 +57,7 @@ <h3>Dynamically change PDF source</h3>
       <template>
         <paper-button raised id="one">PDF One</paper-button>
         <paper-button raised id="another">PDF Two</paper-button>
-        <pdf-element id="pdf" show-spinner  width=800 height=600></pdf-element>
-        <script>
-          window.onload = function() {
-            document.querySelector("#one").addEventListener("click", function() {
-              document.getElementById("pdf").setAttribute("src", "./pdf.pdf");
-            });
-            document.querySelector("#another").addEventListener("click", function() {
-              document.getElementById("pdf").setAttribute("src", "./example.pdf");
-            });
-          }
-        </script>
+        <pdf-element id="pdf" show-spinner width=800 height=600></pdf-element>
       </template>
       <script>
         window.onload = function() {
diff --git a/pdf-element.html b/pdf-element.html
index 78cac99..cd6b141 100644
--- a/pdf-element.html
+++ b/pdf-element.html
@@ -151,7 +151,8 @@
          */
         src: {
           type: String,
-          notify: true
+          notify: true,
+          observer: '_srcChanged'
         },
         /**
          * The z-depth of this element, from 0-5. Setting to 0 will remove the shadow, and each increasing number greater than 0 will be "deeper" than the last.
@@ -200,15 +201,13 @@
         this.fileName = this.src.split('/').pop();
         this.currentPage = 1;
       },
-      attributeChanged: function(attrName, oldVal, newVal) {
-        if (attrName == 'src' && newVal != '') {
-          if (typeof this.instance == 'undefined') this._initializeReader();
-          else {
-            this.instance.changePDFSource(newVal);
-            this.currentPage = 1;
-            this.totalPages = this.instance.totalPages;
-            this.fileName = this.src.split('/').pop();
-          }
+      _srcChanged: function(newVal) {
+        if (typeof this.instance == 'undefined') this._initializeReader();
+        else {
+          this.instance.changePDFSource(newVal);
+          this.currentPage = 1;
+          this.totalPages = this.instance.totalPages;
+          this.fileName = this.src.split('/').pop();
         }
       },
       zoomIn: function() {