[Fetch API] Appending headers of the same name should have their values

third_party/WebKit/Source/modules/fetch/FetchHeaderList.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/FetchHeaderList.h"
 
 #include "core/fetch/FetchUtils.h"
 #include "platform/network/HTTPParsers.h"
 #include "wtf/PtrUtil.h"
 #include <algorithm>
@@ skipping 69 matching lines @@
   for (size_t i = 0; i < m_headerList.size();) {
     if (m_headerList[i]->first == lowercasedName)
       m_headerList.remove(i);
     else
       ++i;
   }
 }
 
 bool FetchHeaderList::get(const String& name, String& result) const {
   const String lowercasedName = name.lower();
-  for (size_t i = 0; i < m_headerList.size(); ++i) {
-    if (m_headerList[i]->first == lowercasedName) {
-      result = m_headerList[i]->second;
-      return true;
+  bool found = false;
+  for (const auto& header : m_headerList) {
+    if (header->first == lowercasedName) {
+      if (!found) {
+        result = "";
+        result.append(header->second);
+        found = true;
+      } else {
+        result.append(",");
+        result.append(header->second);
+      }
     }
   }
-  return false;
+  return found;
 }
 
 void FetchHeaderList::getAll(const String& name, Vector<String>& result) const {
   const String lowercasedName = name.lower();
   result.clear();
   for (size_t i = 0; i < m_headerList.size(); ++i) {
     if (m_headerList[i]->first == lowercasedName)
       result.append(m_headerList[i]->second);
   }
 }
@@ skipping 47 matching lines @@
   return isValidHTTPToken(name);
 }
 
 bool FetchHeaderList::isValidHeaderValue(const String& value) {
   // "A value is a byte sequence that matches the field-value token production
   // and contains no 0x0A or 0x0D bytes."
   return isValidHTTPHeaderValue(value);
 }
 
 }  // namespace blink