--- webkitgtk-2.52.1.old/Source/WebKit/WebProcess/InjectedBundle/API/gtk/DOM/WebKitDOMDOMWindow.cpp
+++ webkitgtk-2.52.1/Source/WebKit/WebProcess/InjectedBundle/API/gtk/DOM/WebKitDOMDOMWindow.cpp
@@ -1082,10 +1082,7 @@
     JSRetainPtr<JSStringRef> jsString(Adopt, JSStringCreateWithUTF8CString(message));
     JSValueRef jsStringValue = JSValueMakeString(toRef(globalObject), jsString.get());
 
-    auto result = handler->postMessage(*globalObject, toJS(globalObject, jsStringValue), adoptRef(*(promise.leakRef())));
-    if (result.hasException())
-        return FALSE;
-
+    handler->postMessage(*globalObject, toJS(globalObject, jsStringValue), adoptRef(*(promise.leakRef())));
     return TRUE;
 #else
     return FALSE;