From 55aa47af9fcbff0a041d452175977f7120f39ad3 Mon Sep 17 00:00:00 2001
From: Gijs Kruitbosch <gijskruitbosch@gmail.com>
Date: Wed, 1 Apr 2015 13:40:25 +0100
Subject: [PATCH] Bug 1147487 - don't try to reader-ize non-HTML documents,
 r=margaret,jaws

--HG--
extra : rebase_source : 107eb010f3c7967e038b7a0b4895425e4e3e7312
---
 toolkit/components/reader/ReaderMode.jsm | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/toolkit/components/reader/ReaderMode.jsm b/toolkit/components/reader/ReaderMode.jsm
index 84184648a204..4c620b99609d 100644
--- a/toolkit/components/reader/ReaderMode.jsm
+++ b/toolkit/components/reader/ReaderMode.jsm
@@ -68,8 +68,12 @@ this.ReaderMode = {
    * @return boolean Whether or not we should show the reader mode button.
    */
   isProbablyReaderable: function(doc) {
-    let uri = Services.io.newURI(doc.location.href, null, null);
+    // Only care about 'real' HTML documents:
+    if (doc.mozSyntheticDocument || !(doc instanceof doc.defaultView.HTMLDocument)) {
+      return false;
+    }
 
+    let uri = Services.io.newURI(doc.location.href, null, null);
     if (!this._shouldCheckUri(uri)) {
       return false;
     }