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

third_party/WebKit/Source/modules/fetch/Headers.h

 // 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.
 
 #ifndef Headers_h
 #define Headers_h
 
 #include "bindings/core/v8/Iterable.h"
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/ScriptWrappable.h"
@@ skipping 37 matching lines @@
   String get(const String& key, ExceptionState&);
   Vector<String> getAll(const String& key, ExceptionState&);
   bool has(const String& key, ExceptionState&);
   void set(const String& key, const String& value, ExceptionState&);
 
   void SetGuard(Guard guard) { guard_ = guard; }
   Guard GetGuard() const { return guard_; }
 
   // These methods should only be called when size() would return 0.
   void FillWith(const Headers*, ExceptionState&);
-  void FillWith(const Vector<Vector<String>>&, ExceptionState&);
-  void FillWith(const Vector<std::pair<String, String>>&, ExceptionState&);
+  void FillWith(
+      const ByteStringSequenceSequenceOrByteStringByteStringRecordOrHeaders&,

[yhirano, 2017/04/28 10:07:44]

Could you provide a typedef for this type? Maybe HeadersInit?

[Raphael Kubo da Costa (rakuco), 2017/05/01 09:57:12]

Done.

+      ExceptionState&);
 
   FetchHeaderList* HeaderList() const { return header_list_; }
   DECLARE_TRACE();
 
  private:
   Headers();
   // Shares the FetchHeaderList. Called when creating a Request or Response.
   explicit Headers(FetchHeaderList*);
 
+  // These methods should only be called when size() would return 0.
+  void FillWith(const Vector<Vector<String>>&, ExceptionState&);
+  void FillWith(const Vector<std::pair<String, String>>&, ExceptionState&);
+
   Member<FetchHeaderList> header_list_;
   Guard guard_;
 
   IterationSource* StartIteration(ScriptState*, ExceptionState&) override;
 };
 
 }  // namespace blink
 
 #endif  // Headers_h