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

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

Index: third_party/WebKit/Source/modules/fetch/Headers.h
diff --git a/third_party/WebKit/Source/modules/fetch/Headers.h b/third_party/WebKit/Source/modules/fetch/Headers.h
index 52c4604afa298f00d87f6fd7fd2ed68db9ce82a4..4a83ebcccb0c60d016b7465c915b404863122aa7 100644
--- a/third_party/WebKit/Source/modules/fetch/Headers.h
+++ b/third_party/WebKit/Source/modules/fetch/Headers.h
@@ -14,6 +14,7 @@
 
 namespace blink {
 
+class ByteStringSequenceSequenceOrDictionaryOrHeaders;
 class Dictionary;
 class ExceptionState;
 
@@ -32,11 +33,9 @@ class MODULES_EXPORT Headers final : public GarbageCollected<Headers>,
     NoneGuard
   };
 
-  static Headers* create();
   static Headers* create(ExceptionState&);
-  static Headers* create(const Headers*, ExceptionState&);
-  static Headers* create(const Vector<Vector<String>>&, ExceptionState&);
-  static Headers* create(const Dictionary&, ExceptionState&);
+  static Headers* create(const ByteStringSequenceSequenceOrDictionaryOrHeaders&,
+                         ExceptionState&);
 
   // Shares the FetchHeaderList. Called when creating a Request or Response.
   static Headers* create(FetchHeaderList*);