Change BodyStreamBuffer to be FetchDataConsumerHandle-based and enable backpressure in Fetch API

Source/modules/fetch/FetchResponseData.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 FetchResponseData_h
 #define FetchResponseData_h
 
 #include "modules/ModulesExport.h"
 #include "platform/heap/Handle.h"
 #include "platform/weborigin/KURL.h"
 #include "public/platform/WebServiceWorkerRequest.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/text/AtomicString.h"
 
 namespace blink {
 
 class BlobDataHandle;
-class BodyStreamBuffer;
+class BodyStreamBuffer2;
+class ExecutionContext;
+class FetchDataConsumerHandle;
 class FetchHeaderList;
 class WebServiceWorkerResponse;
 
 class MODULES_EXPORT FetchResponseData final : public GarbageCollectedFinalized<FetchResponseData> {
     WTF_MAKE_NONCOPYABLE(FetchResponseData);
 public:
     // "A response has an associated type which is one of basic, CORS, default,
     // error, and opaque. Unless stated otherwise, it is default."
     enum Type { BasicType, CORSType, DefaultType, ErrorType, OpaqueType };
     // "A response can have an associated termination reason which is one of
     // end-user abort, fatal, and timeout."
     enum TerminationReason { EndUserAbortTermination, FatalTermination, TimeoutTermination };
 
     static FetchResponseData* create();
     static FetchResponseData* createNetworkErrorResponse();
-    static FetchResponseData* createWithBuffer(BodyStreamBuffer*);
+    static FetchResponseData* createWithBuffer(BodyStreamBuffer2*);
 
     FetchResponseData* createBasicFilteredResponse();
     FetchResponseData* createCORSFilteredResponse();
     FetchResponseData* createOpaqueFilteredResponse();
 
-    FetchResponseData* clone();
+    FetchResponseData* clone(ExecutionContext*);
 
     Type type() const { return m_type; }
     const KURL& url() const { return m_url; }
     unsigned short status() const { return m_status; }
     AtomicString statusMessage() const { return m_statusMessage; }
     FetchHeaderList* headerList() const { return m_headerList.get(); }
-    PassRefPtr<BlobDataHandle> blobDataHandle() const { return m_blobDataHandle; }
-    BodyStreamBuffer* buffer() const { return m_buffer; }
+    BodyStreamBuffer2* buffer() const { return m_buffer; }
     String mimeType() const;
-    PassRefPtr<BlobDataHandle> internalBlobDataHandle() const;
-    BodyStreamBuffer* internalBuffer() const;
+    BodyStreamBuffer2* internalBuffer() const;
     String internalMIMEType() const;
 
     void setURL(const KURL& url) { m_url = url; }
     void setStatus(unsigned short status) { m_status = status; }
     void setStatusMessage(AtomicString statusMessage) { m_statusMessage = statusMessage; }
-    void setBlobDataHandle(PassRefPtr<BlobDataHandle>);
     void setMIMEType(const String& type) { m_mimeType = type; }
 
-    // If the type is Default, replaces |m_buffer| and sets |m_blobDataHandle|
-    // to nullptr. If the type is Basic or CORS, replaces |m_buffer| and sets
-    // |m_blobDataHandle| to nullptr, and does the same operation to
-    // |m_internalResponse|. If the type is Error or Opaque, does nothing.
-    void replaceBodyStreamBuffer(BodyStreamBuffer*);
+    // If the type is Default, replaces |m_buffer|.
+    // If the type is Basic or CORS, replaces |m_buffer| and
+    // |m_internalResponse->m_buffer|.
+    // If the type is Error or Opaque, does nothing.
+    void replaceBodyStreamBuffer(BodyStreamBuffer2*);
 
-    void populateWebServiceWorkerResponse(WebServiceWorkerResponse&);
+    // Does not call response.setBlobDataHandle().
+    void populateWebServiceWorkerResponse(WebServiceWorkerResponse& /* response */);
 
     DECLARE_TRACE();
 
 private:
     FetchResponseData(Type, unsigned short, AtomicString);
 
     Type m_type;
     OwnPtr<TerminationReason> m_terminationReason;
     KURL m_url;
     unsigned short m_status;
     AtomicString m_statusMessage;
     Member<FetchHeaderList> m_headerList;
     RefPtr<BlobDataHandle> m_blobDataHandle;
     Member<FetchResponseData> m_internalResponse;
-    Member<BodyStreamBuffer> m_buffer;
+    Member<BodyStreamBuffer2> m_buffer;
     String m_mimeType;
 };
 
 } // namespace blink
 
 #endif // FetchResponseData_h