CREDENTIAL: Extend FormData opacity to created Request objects

Source/modules/fetch/RequestInit.cpp

Index: Source/modules/fetch/RequestInit.cpp
diff --git a/Source/modules/fetch/RequestInit.cpp b/Source/modules/fetch/RequestInit.cpp
index d2763a645f7df8e72bd15f1294cc98dcaa97b032..3b8690d3ef17d62743a2d3772326e4977fafb232 100644
--- a/Source/modules/fetch/RequestInit.cpp
+++ b/Source/modules/fetch/RequestInit.cpp
@@ -12,6 +12,7 @@
 #include "bindings/core/v8/V8Blob.h"
 #include "bindings/core/v8/V8FormData.h"
 #include "core/fileapi/Blob.h"
+#include "core/html/DOMFormData.h"
 #include "modules/fetch/FetchBlobDataConsumerHandle.h"
 #include "modules/fetch/FetchFormDataConsumerHandle.h"
 #include "modules/fetch/Headers.h"
@@ -21,6 +22,7 @@
 namespace blink {
 
 RequestInit::RequestInit(ExecutionContext* context, const Dictionary& options, ExceptionState& exceptionState)
+    : opaque(false)
 {
     DictionaryHelper::get(options, "method", method);
     DictionaryHelper::get(options, "headers", headers);
@@ -49,7 +51,10 @@ RequestInit::RequestInit(ExecutionContext* context, const Dictionary& options, E
         contentType = blobDataHandle->type();
         body = FetchBlobDataConsumerHandle::create(context, blobDataHandle.release());
     } else if (V8FormData::hasInstance(v8Body, isolate)) {
-        RefPtr<FormData> formData = V8FormData::toImpl(v8::Local<v8::Object>::Cast(v8Body))->createMultiPartFormData();
+        DOMFormData* domFormData = V8FormData::toImpl(v8::Local<v8::Object>::Cast(v8Body));
+        opaque = domFormData->opaque();
+
+        RefPtr<FormData> formData = domFormData->createMultiPartFormData();
         // Here we handle formData->boundary() as a C-style string. See
         // FormDataBuilder::generateUniqueBoundaryString.
         contentType = AtomicString("multipart/form-data; boundary=", AtomicString::ConstructFromLiteral) + formData->boundary().data();