Some fixes for macOS

App/Web Process Bundle Bridge/SBRProcessBundleBridge.m

@@ -66,6 +66,11 @@
         // Inject bundle
         _WKProcessPoolConfiguration *poolConfiguration = [[_WKProcessPoolConfiguration alloc] init];
         NSURL *bundleURL = [[[NSBundle mainBundle] builtInPlugInsURL] URLByAppendingPathComponent:@"SBrowserProcessBundle.bundle"];
+        
+        // Make sure it exists. Bail if otherwise.
+        NSBundle *pluginBundle = [NSBundle bundleWithURL:bundleURL];
+        NSAssert(pluginBundle != nil, @"Attix process bundle not found at %@", bundleURL.path);
+        
         [poolConfiguration setInjectedBundleURL:bundleURL];
 
         // Set up process pool