Cherry-pick 268085@main (ab8e3bc). https://bugs.webkit.org/show_bug.c…

…gi?id=261674

    [GTK4] NativeWebWheelEvent crashes on wheel event tests
    https://bugs.webkit.org/show_bug.cgi?id=261674

    Reviewed by Michael Catanzaro.

    The GdkEvent API in GTK4 won't play ball when given a NULL event.
    When synthesizing wheel events we might pass a NULL event to the
    event factory, so make sure that the methods that call GDK API
    on it are NULL-safe.

    * Source/WebCore/platform/gtk/GtkUtilities.cpp:
    (WebCore::wallTimeForEvent):
    * Source/WebKit/Shared/gtk/WebEventFactory.cpp:
    (WebKit::modifiersForEvent):

    Canonical link: https://commits.webkit.org/268085@main

Source/WebCore/platform/gtk/GtkUtilities.cpp

@@ -128,6 +128,8 @@ WallTime wallTimeForEvent(const GdkEvent* event)
     // g_get_monotonic_time() continues to do so as well, and so long as
     // MonotonicTime continues to use g_get_monotonic_time().
 #if USE(GTK4)
+    if (!event)
+        return WallTime::now();
     auto time = gdk_event_get_time(const_cast<GdkEvent*>(event));
 #else
     auto time = gdk_event_get_time(event);

Source/WebKit/Shared/gtk/WebEventFactory.cpp

@@ -58,7 +58,7 @@ static inline OptionSet<WebEventModifier> modifiersForEvent(const GdkEvent* even
     GdkModifierType state;
 
     // Check for a valid state in GdkEvent.
-    if (!gdk_event_get_state(event, &state))
+    if (!event || !gdk_event_get_state(event, &state))
         return modifiers;
 
     if (state & GDK_CONTROL_MASK)