Improve memory estimate of SpdySessionPool in net/ MemoryDumpProvider.

net/spdy/http2_priority_dependencies.h

 // Copyright 2016 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_HTTP2_PRIORITY_DEPENDENCIES_H_
 #define NET_SPDY_HTTP2_PRIORITY_DEPENDENCIES_H_
 
 #include <list>
 #include <map>
 
@@ skipping 29 matching lines @@
     bool exclusive;
   };
 
   // Called when a stream's priority has changed. Returns a list of
   // dependency updates that should be sent to the server to describe
   // the requested priority change. The updates should be sent in the
   // given order.
   std::vector<DependencyUpdate> OnStreamUpdate(SpdyStreamId id,
                                                SpdyPriority new_priority);
 
+  // Returns the estimate of dynamically allocated memory in bytes.
+  size_t EstimateMemoryUsage() const;
+
  private:
   // The requirements for the internal data structure for this class are:
   //     a) Constant time insertion of entries at the end of the list,
   //     b) Fast removal of any entry based on its id.
   //     c) Constant time lookup of the entry at the end of the list.
   // std::list would satisfy (a) & (c), but some form of map is
   // needed for (b).  The priority must be included in the map
   // entries so that deletion can determine which list in id_priority_lists_
   // to erase from.
   using IdList = std::list<std::pair<SpdyStreamId, SpdyPriority>>;
@@ skipping 18 matching lines @@
 
   // Finds the stream just below |id| in the total order.
   // Returns false if there are no streams with a lower priority.
   // Otherwise, returns true and sets |*child|.
   bool ChildOfStream(SpdyStreamId id, IdList::iterator* child);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_HTTP2_PRIORITY_DEPENDENCIES_H_