Make Response::body return v8-extra based stream behind flag

third_party/WebKit/Source/modules/fetch/Body.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 Body_h
 #define Body_h
 
 #include "bindings/core/v8/ActiveScriptWrappable.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptValue.h"
@@ skipping 27 matching lines @@
     USING_GARBAGE_COLLECTED_MIXIN(Body);
 public:
     explicit Body(ExecutionContext*);
     ~Body() override { }
 
     ScriptPromise arrayBuffer(ScriptState*);
     ScriptPromise blob(ScriptState*);
     ScriptPromise formData(ScriptState*);
     ScriptPromise json(ScriptState*);
     ScriptPromise text(ScriptState*);
-    ReadableByteStream* bodyWithUseCounter();
+    ScriptValue bodyWithUseCounter(ScriptState*);
     virtual BodyStreamBuffer* bodyBuffer() = 0;
     virtual const BodyStreamBuffer* bodyBuffer() const = 0;
-    ScriptValue v8ExtraStreamBody(ScriptState*);
 
     virtual bool bodyUsed();
     bool isBodyLocked();
 
     // ActiveScriptWrappable override.
     bool hasPendingActivity() const override;
 
     DEFINE_INLINE_VIRTUAL_TRACE()
     {
         ActiveDOMObject::trace(visitor);
     }
 
 private:
-    ReadableByteStream* body();
     virtual String mimeType() const = 0;
 
     // Body consumption algorithms will reject with a TypeError in a number of
     // error conditions. This method wraps those up into one call which returns
     // an empty ScriptPromise if the consumption may proceed, and a
     // ScriptPromise rejected with a TypeError if it ought to be blocked.
     ScriptPromise rejectInvalidConsumption(ScriptState*);
 };
 
 } // namespace blink
 
 #endif // Body_h