Improve memory estimate of SpdySessionPool in net/ MemoryDumpProvider.

net/spdy/spdy_buffer.h

Index: net/spdy/spdy_buffer.h
diff --git a/net/spdy/spdy_buffer.h b/net/spdy/spdy_buffer.h
index 0d9ffbf248b9ab0490d7fa98f555d9a1af401765..c2271a5fea439fca8e73e8ea825de0c792ae3855 100644
--- a/net/spdy/spdy_buffer.h
+++ b/net/spdy/spdy_buffer.h
@@ -83,6 +83,9 @@ class NET_EXPORT_PRIVATE SpdyBuffer {
   // http://crbug.com/249725 .)
   IOBuffer* GetIOBufferForRemainingData();
 
+  // Returns the estimate of dynamically allocated memory in bytes.
+  size_t EstimateMemoryUsage() const;
+
  private:
   void ConsumeHelper(size_t consume_size, ConsumeSource consume_source);