Fetch: Make Headers' constructor match the current spec IDL.

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/V8Binding.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"
 #include "platform/weborigin/ReferrerPolicy.h"
 
 namespace blink {
 
 // TODO(yiyix): Verify if any DictionaryHelper::get should be replaced with
 // DictionaryHelper::getWithUndefinedCheck.
 RequestInit::RequestInit(ExecutionContext* context,
                          const Dictionary& options,
                          ExceptionState& exception_state)
     : are_any_members_set(false) {
   are_any_members_set |= DictionaryHelper::Get(options, "method", method);
-  are_any_members_set |= DictionaryHelper::Get(options, "headers", headers);
-  if (!headers) {
-    Vector<Vector<String>> headers_vector;
-    if (DictionaryHelper::Get(options, "headers", headers_vector,
-                              exception_state)) {
-      headers = Headers::Create(headers_vector, exception_state);
-      are_any_members_set = true;
-    } else {
-      are_any_members_set |=
-          DictionaryHelper::Get(options, "headers", headers_dictionary);
-    }
-  }
+
+  // From https://github.com/whatwg/fetch/issues/479:
+  // - undefined is the same as "this member has not been passed".
+  // - {} means "the list of headers is empty", so the member has been set.
+  // - null is an invalid value for both sequences and records, but it is not
+  //   the same as undefined: a value has been set, even if invalid, and will
+  //   throw a TypeError later when it gets converted to a HeadersInit object.
+  v8::Local<v8::Value> v8_headers;
+  bool is_header_set = DictionaryHelper::Get(options, "headers", v8_headers) &&
+                       !v8_headers->IsUndefined();
+  are_any_members_set |= is_header_set;
+
   are_any_members_set |= DictionaryHelper::Get(options, "mode", mode);
   are_any_members_set |= DictionaryHelper::Get(options, "redirect", redirect);
   AtomicString referrer_string;
   bool is_referrer_string_set = DictionaryHelper::GetWithUndefinedCheck(
       options, "referrer", referrer_string);
   are_any_members_set |= is_referrer_string_set;
   are_any_members_set |= DictionaryHelper::Get(options, "integrity", integrity);
   AtomicString referrer_policy_string;
   bool is_referrer_policy_set =
       DictionaryHelper::Get(options, "referrerPolicy", referrer_policy_string);
@@ skipping 37 matching lines @@
         referrer.referrer_policy =
             kReferrerPolicyNoReferrerWhenDowngradeOriginWhenCrossOrigin;
       } 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);
+    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
       // the browser and renderer processes to deal with service workers is
       // equally painful. There should be no developer-visible difference in
       // behavior with this option, except that the `Content-Type` header will
       // be set early. That seems reasonable.
@@ skipping 37 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