REGRESSION (270339@main): [ iOS17 ] TestWebKitAPI.WebKit.InvalidConfi…

…guration is a crash failure

https://bugs.webkit.org/show_bug.cgi?id=264609
rdar://118242512

Reviewed by Alex Christensen.

* Source/WebKit/UIProcess/Cocoa/WKWebViewContentProviderRegistry.mm:
(-[WKWebViewContentProviderRegistry initWithConfiguration:]):
ObjC null rules stop applying when you start using C++ ivars.

Canonical link: https://commits.webkit.org/270603@main

Source/WebKit/UIProcess/Cocoa/WKWebViewContentProviderRegistry.mm

@@ -52,7 +52,7 @@ - (instancetype)initWithConfiguration:(WKWebViewConfiguration *)configuration
         return nil;
 
 #if ENABLE(WKPDFVIEW)
-    if (!configuration.preferences->_preferences->unifiedPDFEnabled()) {
+    if (!configuration.preferences || !configuration.preferences->_preferences->unifiedPDFEnabled()) {
         for (auto& type : WebCore::MIMETypeRegistry::pdfMIMETypes())
             [self registerProvider:[WKPDFView class] forMIMEType:@(type.characters())];
     }