Support full range of PreflightPolicy over WebURLLoaderOptions

public/web/WebURLLoaderOptions.h

Index: public/web/WebURLLoaderOptions.h
diff --git a/public/web/WebURLLoaderOptions.h b/public/web/WebURLLoaderOptions.h
index 045595d74c11a830d98edb6cc5367f3a116e0cea..a0c135df17ef4f2d56ddfe4da096bd64239256a7 100644
--- a/public/web/WebURLLoaderOptions.h
+++ b/public/web/WebURLLoaderOptions.h
@@ -41,20 +41,26 @@ struct WebURLLoaderOptions {
         CrossOriginRequestPolicyAllow
     };
 
+    enum PreflightPolicy {
+        ConsiderPreflight,
+        ForcePreflight,
+        PreventPreflight
+    };
+
     WebURLLoaderOptions()
         : untrustedHTTP(false)
         , sniffContent(false)
         , allowCredentials(false)
-        , forcePreflight(false)
         , exposeAllResponseHeaders(false)
+        , preflightPolicy(ConsiderPreflight)
         , crossOriginRequestPolicy(CrossOriginRequestPolicyDeny)
         { }
 
     bool untrustedHTTP; // Whether to validate the method and headers as if this was an XMLHttpRequest.
     bool sniffContent; // Whether to sniff content.
     bool allowCredentials; // Whether to send HTTP credentials and cookies with the request.
-    bool forcePreflight; // If policy is to use access control, whether to force a preflight for GET, HEAD, and POST requests.
     bool exposeAllResponseHeaders; // If policy is to use access control, whether to expose non-whitelisted response headers to the client.
+    PreflightPolicy preflightPolicy;
     CrossOriginRequestPolicy crossOriginRequestPolicy;
 };