Implment BytesConsumer::tee

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

 // Copyright 2016 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 BytesConsumer_h
 #define BytesConsumer_h
 
 #include "modules/ModulesExport.h"
 #include "platform/blob/BlobData.h"
 #include "platform/heap/Handle.h"
 #include "platform/network/EncodedFormData.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
+class ExecutionContext;
+
 // BytesConsumer represents the "consumer" side of a data pipe. A user
 // can read data from it.
 //
 // A BytesConsumer is bound to the thread on which it is created.
 // BytesConsumer has four states: waiting, readable, closed and errored. Once
 // the state becomes closed or errored, it will never change. |readable| means
 // that the BytesConsumer is ready to read non-empty bytes synchronously.
 class MODULES_EXPORT BytesConsumer : public GarbageCollectedFinalized<BytesConsumer> {
 public:
     enum class Result {
@@ skipping 105 matching lines @@
     virtual PublicState getPublicState() const = 0;
 
     // Returns the associated error of this object. This function can be called
     // only when errored.
     virtual Error getError() const = 0;
 
     // Each implementation should return a string that represents the
     // implementation for debug purpose.
     virtual String debugName() const = 0;
 
+    // Creates two BytesConsumer both of which represent the data sequence that
+    // would be read from |src| and store them to |*dest1| and |*dest2|.
+    // |src| must not have a client when called.
+    static void tee(ExecutionContext*, BytesConsumer* src, BytesConsumer** dest1, BytesConsumer** dest2);
+
     DEFINE_INLINE_VIRTUAL_TRACE() {}
 
 protected:
     // This InternalState directly corresponds to the states in the class
     // comments. This enum is defined here for subclasses.
     enum class InternalState {
         Readable,
         Waiting,
         Closed,
         Errored,
@@ skipping 11 matching lines @@
             return PublicState::Errored;
         }
         NOTREACHED();
         return PublicState::ReadableOrWaiting;
     }
 };
 
 } // namespace blink
 
 #endif // BytesConsumer_h