diff --git a/widget/android/nsScreenManagerAndroid.cpp b/widget/android/nsScreenManagerAndroid.cpp
index 44c439199897..1057d9fa53f1 100644
--- a/widget/android/nsScreenManagerAndroid.cpp
+++ b/widget/android/nsScreenManagerAndroid.cpp
@@ -3,6 +3,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#define MOZ_FATAL_ASSERTIONS_FOR_THREAD_SAFETY
+
 #include "nsScreenManagerAndroid.h"
 #include "nsWindow.h"
 #include "AndroidBridge.h"
diff --git a/widget/xpwidgets/nsBaseScreen.cpp b/widget/xpwidgets/nsBaseScreen.cpp
index a62e07c49d6f..352ef2ecd7cd 100644
--- a/widget/xpwidgets/nsBaseScreen.cpp
+++ b/widget/xpwidgets/nsBaseScreen.cpp
@@ -5,6 +5,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#define MOZ_FATAL_ASSERTIONS_FOR_THREAD_SAFETY
+
 #include "nsBaseScreen.h"
 
 NS_IMPL_ISUPPORTS1(nsBaseScreen, nsIScreen)
diff --git a/xpcom/glue/nsDebug.h b/xpcom/glue/nsDebug.h
index 3ad1a949d1aa..9f8b06bf0681 100644
--- a/xpcom/glue/nsDebug.h
+++ b/xpcom/glue/nsDebug.h
@@ -315,10 +315,13 @@
 /*****************************************************************************/
 
 #ifdef XPCOM_GLUE
-#define NS_CheckThreadSafe(owningThread, msg)
+  #define NS_CheckThreadSafe(owningThread, msg)
+#elif defined MOZ_FATAL_ASSERTIONS_FOR_THREAD_SAFETY
+  #define NS_CheckThreadSafe(owningThread, msg)                 \
+    NS_ABORT_IF_FALSE(owningThread == PR_GetCurrentThread(), msg)
 #else
-#define NS_CheckThreadSafe(owningThread, msg)                 \
-  NS_ASSERTION(owningThread == PR_GetCurrentThread(), msg)
+  #define NS_CheckThreadSafe(owningThread, msg)                 \
+    NS_ASSERTION(owningThread == PR_GetCurrentThread(), msg)
 #endif
 
 /* When compiling the XPCOM Glue on Windows, we pretend that it's going to