Improve memory estimate of SpdySessionPool in net/ MemoryDumpProvider.

net/spdy/spdy_buffer_producer.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 NET_SPDY_SPDY_BUFFER_PRODUCER_H_
 #define NET_SPDY_SPDY_BUFFER_PRODUCER_H_
 
 #include <memory>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "net/base/net_export.h"
 
 namespace net {
 
 class SpdyBuffer;
 
 // An object which provides a SpdyBuffer for writing. We pass these
 // around instead of SpdyBuffers since some buffers have to be
 // generated "just in time".
 class NET_EXPORT_PRIVATE SpdyBufferProducer {
  public:
   SpdyBufferProducer();
 
   // Produces the buffer to be written. Will be called at most once.
   virtual std::unique_ptr<SpdyBuffer> ProduceBuffer() = 0;
 
   virtual ~SpdyBufferProducer();
 
+  // Returns the estimate of dynamically allocated memory in bytes.
+  virtual size_t EstimateMemoryUsage() const = 0;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(SpdyBufferProducer);
 };
 
 // A simple wrapper around a single SpdyBuffer.
 class NET_EXPORT_PRIVATE SimpleBufferProducer : public SpdyBufferProducer {
  public:
   explicit SimpleBufferProducer(std::unique_ptr<SpdyBuffer> buffer);
 
   ~SimpleBufferProducer() override;
 
   std::unique_ptr<SpdyBuffer> ProduceBuffer() override;
 
+  size_t EstimateMemoryUsage() const override;
+
  private:
   std::unique_ptr<SpdyBuffer> buffer_;
 
   DISALLOW_COPY_AND_ASSIGN(SimpleBufferProducer);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_SPDY_BUFFER_PRODUCER_H_