fetch: Align RequestInit's |headers| with the spec.

third_party/WebKit/Source/modules/fetch/RequestInit.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/fetch/RequestInit.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/V8ArrayBuffer.h"
 #include "bindings/core/v8/V8ArrayBufferView.h"
 #include "bindings/core/v8/V8BindingForCore.h"
 #include "bindings/core/v8/V8Blob.h"
 #include "bindings/core/v8/V8FormData.h"
 #include "bindings/core/v8/V8URLSearchParams.h"
-#include "bindings/modules/v8/ByteStringSequenceSequenceOrByteStringByteStringRecordOrHeaders.h"
 #include "bindings/modules/v8/V8PasswordCredential.h"
 #include "core/dom/URLSearchParams.h"
 #include "core/fileapi/Blob.h"
 #include "core/html/FormData.h"
 #include "modules/fetch/BlobBytesConsumer.h"
 #include "modules/fetch/FormDataBytesConsumer.h"
 #include "modules/fetch/Headers.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/blob/BlobData.h"
 #include "platform/network/EncodedFormData.h"
@@ skipping 75 matching lines @@
       } else {
         exception_state.ThrowTypeError("Invalid referrer policy");
         return;
       }
     }
   }
 
   v8::Isolate* isolate = ToIsolate(context);
 
   if (is_header_set) {
-    ByteStringSequenceSequenceOrByteStringByteStringRecordOrHeaders
-        headers_init;
     V8ByteStringSequenceSequenceOrByteStringByteStringRecordOrHeaders::toImpl(
-        isolate, v8_headers, headers_init,
-        UnionTypeConversionMode::kNotNullable, exception_state);
-    if (exception_state.HadException())
-      return;
-    headers = Headers::Create(headers_init, exception_state);
+        isolate, v8_headers, headers, UnionTypeConversionMode::kNotNullable,
+        exception_state);
     if (exception_state.HadException())
       return;
   }
 
   if (is_credential_set) {
     if (V8PasswordCredential::hasInstance(v8_credential, isolate)) {
       // TODO(mkwst): According to the spec, we'd serialize this once we touch
       // the network. We're serializing it here, ahead of time, because lifetime
       // issues around ResourceRequest make it pretty difficult to pass a
       // PasswordCredential around at the platform level, and the hop between
@@ skipping 41 matching lines @@
         AtomicString("application/x-www-form-urlencoded;charset=UTF-8");
     body = new FormDataBytesConsumer(context, form_data.Release());
   } else if (v8_body->IsString()) {
     content_type = "text/plain;charset=UTF-8";
     body = new FormDataBytesConsumer(
         ToUSVString(isolate, v8_body, exception_state));
   }
 }
 
 }  // namespace blink