From 785947850f951b60ee24e757328eb2181a3374b7 Mon Sep 17 00:00:00 2001
From: Michael Ratcliffe <mratcliffe@mozilla.com>
Date: Mon, 14 Oct 2019 12:23:13 +0000
Subject: [PATCH] Bug 1583117 - Markup view is blank if an error is thrown
 gathering event listeners r=pbro

Differential Revision: https://phabricator.services.mozilla.com/D49134

--HG--
extra : moz-landing-system : lando
---
 .../actors/inspector/event-collector.js       | 23 ++++++++++++-------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/devtools/server/actors/inspector/event-collector.js b/devtools/server/actors/inspector/event-collector.js
index c0e7d4bab0ad..e37196204915 100644
--- a/devtools/server/actors/inspector/event-collector.js
+++ b/devtools/server/actors/inspector/event-collector.js
@@ -304,15 +304,22 @@ class MainEventCollector {
   }
 
   isChromeHandler(handler) {
-    const handlerPrincipal = Cu.getObjectPrincipal(handler);
+    try {
+      const handlerPrincipal = Cu.getObjectPrincipal(handler);
 
-    // Chrome codebase may register listeners on the page from a frame script or
-    // JSM <video> tags may also report internal listeners, but they won't be
-    // coming from the system principal. Instead, they will be using an expanded
-    // principal.
-    return (
-      handlerPrincipal.isSystemPrincipal || handlerPrincipal.isExpandedPrincipal
-    );
+      // Chrome codebase may register listeners on the page from a frame script or
+      // JSM <video> tags may also report internal listeners, but they won't be
+      // coming from the system principal. Instead, they will be using an expanded
+      // principal.
+      return (
+        handlerPrincipal.isSystemPrincipal ||
+        handlerPrincipal.isExpandedPrincipal
+      );
+    } catch (e) {
+      // Anything from a dead object to a CSP error can leave us here so let's
+      // return false so that we can fail gracefully.
+      return false;
+    }
   }
 }