Issue #1592 - Follow-up: Don't post a restyle event if restyleElement is null

This fixes a potential crash caused if restyleElement is null.

1 files changed, 5 insertions, 2 deletions

diff --git a/dom/base/ShadowRoot.cpp b/dom/base/ShadowRoot.cpp
index 8482da5e99..abf6301123 100644
--- a/dom/base/ShadowRoot.cpp
+++ b/dom/base/ShadowRoot.cpp
@@ -163,6 +163,7 @@ ShadowRoot::AddSlot(HTMLSlotElement* aSlot)
 
       oldSlot->RemoveAssignedNode(assignedNode);
       currentSlot->AppendAssignedNode(assignedNode);
+
       Element* restyleElement;
       if (assignedNode->IsElement()) {
         restyleElement = assignedNode->AsElement();
@@ -170,8 +171,10 @@ ShadowRoot::AddSlot(HTMLSlotElement* aSlot)
         // This is likely a text node. Use the host instead.
         restyleElement = GetHost();
       }
-      nsLayoutUtils::PostRestyleEvent(
-        restyleElement, eRestyle_Subtree, nsChangeHint(0));
+      if (restyleElement) {
+        nsLayoutUtils::PostRestyleEvent(
+          restyleElement, eRestyle_Subtree, nsChangeHint(0));
+      }
 
       doEnqueueSlotChange = true;
     }