Improve memory estimate of SpdySessionPool in net/ MemoryDumpProvider.

net/spdy/spdy_write_queue.h

Index: net/spdy/spdy_write_queue.h
diff --git a/net/spdy/spdy_write_queue.h b/net/spdy/spdy_write_queue.h
index acf6b4c30dd9aee7e09514eb02b940a5f1d8f32d..d781f8614a5e7f8cc58c1c63d24bc3a4992a58ac 100644
--- a/net/spdy/spdy_write_queue.h
+++ b/net/spdy/spdy_write_queue.h
@@ -59,6 +59,9 @@ class NET_EXPORT_PRIVATE SpdyWriteQueue {
   // Removes all pending writes.
   void Clear();
 
+  // Returns the estimate of dynamically allocated memory in bytes.
+  size_t EstimateMemoryUsage() const;
+
  private:
   // A struct holding a frame producer and its associated stream.
   struct PendingWrite {
@@ -76,6 +79,8 @@ class NET_EXPORT_PRIVATE SpdyWriteQueue {
     PendingWrite(PendingWrite&& other);
     PendingWrite& operator=(PendingWrite&& other);
 
+    size_t EstimateMemoryUsage() const;
+
     DISALLOW_COPY_AND_ASSIGN(PendingWrite);
   };