[Fetch API] Fix a memory leak with a Response constructed with a ReadableStream

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

 // Copyright 2015 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 ReadableStreamDataConsumerHandle_h
 #define ReadableStreamDataConsumerHandle_h
 
 #include "bindings/core/v8/ScriptValue.h"
 #include "modules/ModulesExport.h"
 #include "modules/fetch/FetchDataConsumerHandle.h"
 #include "wtf/Forward.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 class ScriptState;
 
 // This class is a FetchDataConsumerHandle pulling bytes from ReadableStream
 // implemented with V8 Extras.
 // The stream will be immediately locked by the handle and will never be
 // released.
+//
+// The ReadableStreamReader handle held in a ReadableStreamDataConsumerHandle
+// is weak. A user must guarantee that the ReadableStreamReader object is kept
+// alive appropriately.
 // TODO(yhirano): CURRENTLY THIS HANDLE SUPPORTS READING ONLY FROM THE THREAD ON
 // WHICH IT IS CREATED. FIX THIS.
-// TODO(yhirano): This implementation may cause leaks because the handle and
-// the reader own a strong reference to the associated ReadableStreamReader.
-// Fix it.
 class MODULES_EXPORT ReadableStreamDataConsumerHandle final : public FetchDataConsumerHandle {
     WTF_MAKE_NONCOPYABLE(ReadableStreamDataConsumerHandle);
 public:
-    static PassOwnPtr<ReadableStreamDataConsumerHandle> create(ScriptState* scriptState, ScriptValue stream)
+    static PassOwnPtr<ReadableStreamDataConsumerHandle> create(ScriptState* scriptState, ScriptValue streamReader)
     {
-        return adoptPtr(new ReadableStreamDataConsumerHandle(scriptState, stream));
+        return adoptPtr(new ReadableStreamDataConsumerHandle(scriptState, streamReader));
     }
     ~ReadableStreamDataConsumerHandle() override;
 
 private:
     class ReadingContext;
-    ReadableStreamDataConsumerHandle(ScriptState*, ScriptValue stream);
+    ReadableStreamDataConsumerHandle(ScriptState*, ScriptValue streamReader);
     Reader* obtainReaderInternal(Client*) override;
     const char* debugName() const override { return "ReadableStreamDataConsumerHandle"; }
 
     RefPtr<ReadingContext> m_readingContext;
 };
 
 } // namespace blink
 
 #endif // ReadableStreamDataConsumerHandle_h