Limit the total memory usage for Stream instances

content/browser/streams/stream.h

 // Copyright (c) 2013 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_STREAMS_STREAM_H_
 #define CONTENT_BROWSER_STREAMS_STREAM_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 63 matching lines @@
 
   scoped_ptr<StreamHandle> CreateHandle(const GURL& original_url,
                                         const std::string& mime_type);
   void CloseHandle();
 
   // Indicates whether there is space in the buffer to add more data.
   bool can_add_data() const { return can_add_data_; }
 
   const GURL& url() const { return url_; }
 
+  // For StreamRegistry to remember the last memory usage reported to it.
+  size_t last_total_buffered_bytes() const {
+    return last_total_buffered_bytes_;
+  }
+
  private:
   friend class base::RefCountedThreadSafe<Stream>;
 
   virtual ~Stream();
 
   void OnSpaceAvailable();
   void OnDataAvailable();
 
   size_t data_bytes_read_;
   bool can_add_data_;
 
   GURL url_;
 
   scoped_refptr<net::IOBuffer> data_;
   size_t data_length_;
 
+  // Last value returned by writer_->TotalBufferedBytes() in AddData(). Stored
+  // in order to check memory usage.
+  size_t last_total_buffered_bytes_;
+
   scoped_ptr<ByteStreamWriter> writer_;
   scoped_ptr<ByteStreamReader> reader_;
 
   StreamRegistry* registry_;
   StreamReadObserver* read_observer_;
   StreamWriteObserver* write_observer_;
 
   StreamHandleImpl* stream_handle_;
 
   base::WeakPtrFactory<Stream> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(Stream);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_STREAMS_STREAM_H_