diff --git a/mozilla/uriloader/base/nsDocLoader.cpp b/mozilla/uriloader/base/nsDocLoader.cpp
index 833efc89f46..b7914b4a7c0 100644
--- a/mozilla/uriloader/base/nsDocLoader.cpp
+++ b/mozilla/uriloader/base/nsDocLoader.cpp
@@ -1748,7 +1748,7 @@ public:
     NS_IF_ADDREF(mWebShell);
   }
 
-  ~nsWebShellEventSinkGetter() {
+  virtual ~nsWebShellEventSinkGetter() {
     NS_IF_RELEASE(mWebShell);
   }
 
diff --git a/mozilla/webshell/src/nsDocLoader.cpp b/mozilla/webshell/src/nsDocLoader.cpp
index 833efc89f46..b7914b4a7c0 100644
--- a/mozilla/webshell/src/nsDocLoader.cpp
+++ b/mozilla/webshell/src/nsDocLoader.cpp
@@ -1748,7 +1748,7 @@ public:
     NS_IF_ADDREF(mWebShell);
   }
 
-  ~nsWebShellEventSinkGetter() {
+  virtual ~nsWebShellEventSinkGetter() {
     NS_IF_RELEASE(mWebShell);
   }