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

third_party/WebKit/Source/modules/fetch/Headers.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/Headers.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/V8IteratorResultValue.h"
 #include "bindings/modules/v8/ByteStringSequenceSequenceOrByteStringByteStringRecordOrHeaders.h"
 #include "core/dom/Iterator.h"
@@ skipping 41 matching lines @@
   return new Headers;
 }
 
 Headers* Headers::Create(
     const ByteStringSequenceSequenceOrByteStringByteStringRecordOrHeaders& init,
     ExceptionState& exception_state) {
   // "The Headers(|init|) constructor, when invoked, must run these steps:"
   // "1. Let |headers| be a new Headers object whose guard is "none".
   Headers* headers = Create(exception_state);
   // "2. If |init| is given, fill headers with |init|. Rethrow any exception."
-  if (init.isByteStringSequenceSequence()) {
-    headers->FillWith(init.getAsByteStringSequenceSequence(), exception_state);
-  } else if (init.isByteStringByteStringRecord()) {
-    headers->FillWith(init.getAsByteStringByteStringRecord(), exception_state);
-  } else if (init.isHeaders()) {
-    // This branch will not be necessary once http://crbug.com/690428 is fixed.
-    headers->FillWith(init.getAsHeaders(), exception_state);
-  } else {
-    NOTREACHED();
-  }
+  headers->FillWith(init, exception_state);
   // "3. Return |headers|."
   return headers;
 }
 
 Headers* Headers::Create(FetchHeaderList* header_list) {
   return new Headers(header_list);
 }
 
 Headers* Headers::Clone() const {
   FetchHeaderList* header_list = header_list_->Clone();
@@ skipping 154 matching lines @@
   // There used to be specific steps describing filling a Headers object with
   // another Headers object, but it has since been removed because it should be
   // handled like a sequence (http://crbug.com/690428).
   for (const auto& header : object->header_list_->List()) {
     append(header.first, header.second, exception_state);
     if (exception_state.HadException())
       return;
   }
 }
 
+void Headers::FillWith(
+    const ByteStringSequenceSequenceOrByteStringByteStringRecordOrHeaders& init,
+    ExceptionState& exception_state) {
+  DCHECK_EQ(header_list_->size(), 0U);
+  if (init.isByteStringSequenceSequence()) {
+    FillWith(init.getAsByteStringSequenceSequence(), exception_state);
+  } else if (init.isByteStringByteStringRecord()) {
+    FillWith(init.getAsByteStringByteStringRecord(), exception_state);
+  } else if (init.isHeaders()) {
+    // This branch will not be necessary once http://crbug.com/690428 is fixed.
+    FillWith(init.getAsHeaders(), exception_state);
+  } else {
+    NOTREACHED();
+  }
+}
+
 void Headers::FillWith(const Vector<Vector<String>>& object,
                        ExceptionState& exception_state) {
   DCHECK(!header_list_->size());
   // "1. If |object| is a sequence, then for each |header| in |object|, run
   //     these substeps:
   //     1. If |header| does not contain exactly two items, then throw a
   //        TypeError.
   //     2. Append |header|’s first item/|header|’s second item to |headers|.
   //        Rethrow any exception."
   for (size_t i = 0; i < object.size(); ++i) {
@@ skipping 28 matching lines @@
   visitor->Trace(header_list_);
 }
 
 PairIterable<String, String>::IterationSource* Headers::StartIteration(
     ScriptState*,
     ExceptionState&) {
   return new HeadersIterationSource(header_list_);
 }
 
 }  // namespace blink