Limit the total memory usage for Stream instances

content/browser/byte_stream.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_BYTE_STREAM_H_
 #define CONTENT_BROWSER_BYTE_STREAM_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 135 matching lines @@
   // full to having space available.  The callback will always be
   // called on the task runner associated with the ByteStreamWriter.
   // This callback will only be called if a call to Write has previously
   // returned false (i.e. the ByteStream has been filled).
   // Multiple calls to this function are supported, though note that it
   // is the callers responsibility to handle races with space becoming
   // available (i.e. in the case of that race either of the before
   // or after callbacks may be called).
   // The callback will not be called after ByteStreamWriter destruction.
   virtual void RegisterCallback(const base::Closure& source_callback) = 0;
+
+  // Returns the number of bytes sent to the reader but not yet reported by
+  // the reader as read.
+  virtual size_t GetTotalBufferedBytes() const = 0;
 };
 
 class CONTENT_EXPORT ByteStreamReader {
  public:
   // Inverse of the fraction of the stream buffer that must be empty before
   // a notification is send to paired Writer that there's more room.
   static const int kFractionReadBeforeWindowUpdate;
 
   enum StreamState { STREAM_EMPTY, STREAM_HAS_DATA, STREAM_COMPLETE };
 
@@ skipping 24 matching lines @@
 CONTENT_EXPORT void CreateByteStream(
     scoped_refptr<base::SequencedTaskRunner> input_task_runner,
     scoped_refptr<base::SequencedTaskRunner> output_task_runner,
     size_t buffer_size,
     scoped_ptr<ByteStreamWriter>* input,
     scoped_ptr<ByteStreamReader>* output);
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_BYTE_STREAM_H_