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

third_party/WebKit/Source/modules/fetch/Request.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/Request.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/V8PrivateProperty.h"
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
@@ skipping 302 matching lines @@
   // Headers object whose guard is "request"."
   Request* r = Request::Create(script_state, request);
   // Perform the following steps:
   // - "Let |headers| be a copy of |r|'s Headers object."
   // - "If |init|'s headers member is present, set |headers| to |init|'s
   //   headers member."
   //
   // We don't create a copy of r's Headers object when init's headers member
   // is present.
   Headers* headers = nullptr;
-  if (!init.headers) {
+  if (init.headers.isNull()) {
     headers = r->getHeaders()->Clone();
   }
   // "Empty |r|'s request's header list."
   r->request_->HeaderList()->ClearList();
   // "If |r|'s request's mode is "no-cors", run these substeps:
   if (r->GetRequest()->Mode() == WebURLRequest::kFetchRequestModeNoCORS) {
     // "If |r|'s request's method is not a simple method, throw a
     // TypeError."
     if (!FetchUtils::IsSimpleMethod(r->GetRequest()->Method())) {
       exception_state.ThrowTypeError("'" + r->GetRequest()->Method() +
                                      "' is unsupported in no-cors mode.");
       return nullptr;
     }
     // "If |request|'s integrity metadata is not the empty string, throw a
     // TypeError."
     if (!request->Integrity().IsEmpty()) {
       exception_state.ThrowTypeError(
           "The integrity attribute is unsupported in no-cors mode.");
       return nullptr;
     }
     // "Set |r|'s Headers object's guard to "request-no-cors"."
     r->getHeaders()->SetGuard(Headers::kRequestNoCORSGuard);
   }
   // "Fill |r|'s Headers object with |headers|. Rethrow any exceptions."
-  if (init.headers) {
-    r->getHeaders()->FillWith(init.headers.Get(), exception_state);
+  if (!init.headers.isNull()) {
+    r->getHeaders()->FillWith(init.headers, exception_state);
   } else {
     DCHECK(headers);
     r->getHeaders()->FillWith(headers, exception_state);
   }
   if (exception_state.HadException())
     return nullptr;
 
   // "If either |init|'s body member is present or |temporaryBody| is
   // non-null, and |request|'s method is `GET` or `HEAD`, throw a TypeError.
   if (init.body || temporary_body ||
@@ skipping 407 matching lines @@
       .Set(request.As<v8::Object>(), body_buffer);
 }
 
 DEFINE_TRACE(Request) {
   Body::Trace(visitor);
   visitor->Trace(request_);
   visitor->Trace(headers_);
 }
 
 }  // namespace blink