From 3e9eba3f0166feb829378a64fd1549c0ca084cd1 Mon Sep 17 00:00:00 2001
From: Gijs <gijskruitbosch@gmail.com>
Date: Mon, 14 Aug 2017 21:42:28 +0100
Subject: [PATCH] Deal with lack of MOZ_PHOTON_THEME on 57+

---
 addon/bootstrap.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/addon/bootstrap.js b/addon/bootstrap.js
index 1d477c543a..800ad668d3 100644
--- a/addon/bootstrap.js
+++ b/addon/bootstrap.js
@@ -230,7 +230,9 @@ let photonPageAction;
 // Does nothing otherwise.  Ideally, in the future, WebExtension page actions
 // and Photon page actions would be one in the same, but they aren't right now.
 function initPhotonPageAction(api) {
-  if (!AppConstants.MOZ_PHOTON_THEME) {
+  // The MOZ_PHOTON_THEME ifdef got removed, but we need to support 55 and 56 as well,
+  // so check if the property exists *and* is false before bailing.
+  if (typeof AppConstants.MOZ_PHOTON_THEME != "undefined" && !AppConstants.MOZ_PHOTON_THEME) {
     // Photon not supported.  Use the WebExtension's browser action.
     return;
   }