From cd49350239e90c84669db6f90cc50c5f75172ef3 Mon Sep 17 00:00:00 2001
From: Daniel Freedman <compismyrx@gmail.com>
Date: Fri, 19 Aug 2016 12:07:14 -0700
Subject: [PATCH 1/2] Handle a baseURI of null

When `ownerDocument.baseURI` is null (detached document, maybe some other cases), `new URL(url, baseURI)` will throw.
Only use `new URL` when `baseURI` is not null.
---
 iron-image.html | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/iron-image.html b/iron-image.html
index da3df07..9149464 100644
--- a/iron-image.html
+++ b/iron-image.html
@@ -396,8 +396,12 @@
       },
 
       _resolveSrc: function(testSrc) {
-        var baseURI = /** @type {string} */(this.ownerDocument.baseURI);
-        return (new URL(Polymer.ResolveUrl.resolveUrl(testSrc, baseURI), baseURI)).href;
+        var baseURI = this.ownerDocument.baseURI;
+        var resolvedUrl = Polymer.ResolveUrl.resolveUrl(testSrc, baseURI);
+        if (baseURI) {
+          resolvedUrl = new URL(resolvedUrl, baseURI).href;
+        }
+        return resolvedUrl;
       }
     });
   </script>

From 897784ccc7be0cf803034b61a568538d96ba7710 Mon Sep 17 00:00:00 2001
From: Daniel Freedman <compismyrx@gmail.com>
Date: Fri, 19 Aug 2016 14:48:55 -0700
Subject: [PATCH 2/2] Just use `new URL`

On second thought, you really only need `new URL`. `Polymer.ResolveUrl.resolveUrl` is just doing the same thing as this.
---
 iron-image.html | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/iron-image.html b/iron-image.html
index 9149464..64d2993 100644
--- a/iron-image.html
+++ b/iron-image.html
@@ -397,11 +397,10 @@
 
       _resolveSrc: function(testSrc) {
         var baseURI = this.ownerDocument.baseURI;
-        var resolvedUrl = Polymer.ResolveUrl.resolveUrl(testSrc, baseURI);
         if (baseURI) {
-          resolvedUrl = new URL(resolvedUrl, baseURI).href;
+          return new URL(testSrc, baseURI).href;
         }
-        return resolvedUrl;
+        return testSrc;
       }
     });
   </script>