Improve memory estimate of SpdySessionPool in net/ MemoryDumpProvider.

net/proxy/proxy_server.cc

Index: net/proxy/proxy_server.cc
diff --git a/net/proxy/proxy_server.cc b/net/proxy/proxy_server.cc
index 76fa0d6224f346fe45f7eacf9c45c255b5252e1d..dc875eb770d06360cb85e593a39816d880a3d4a2 100644
--- a/net/proxy/proxy_server.cc
+++ b/net/proxy/proxy_server.cc
@@ -209,6 +209,10 @@ ProxyServer::Scheme ProxyServer::GetSchemeFromURI(const std::string& scheme) {
   return GetSchemeFromURIInternal(scheme);
 }
 
+size_t ProxyServer::EstimateMemoryUsage() const {
+  return HostPortPair::EstimateMemoryUsage(host_port_pair_);

[Bence, 2017/02/02 14:15:19]

1.It's just a string, how bad can it get?  Few dozen bytes?
2. Why do we not account for memory used by enum Scheme (maybe 64 bits depending
on memory alignment requirements)?
3. Why does HostPortPair::EstimateMemoryUsage() not account for uint16 port,
only the string?

I do not mean to be nitpicking, but since there are multiple kilobyte buffers
and containers hanging around, it feels arbitrary to me to account for few dozen
byte long strings, but not go all the way and account for ints.

[xunjieli, 2017/02/02 14:53:42]

dskiba@ can correct me if I am wrong. My understanding is that EMU() should only
account for dynamically allocated memory. For members(such as enum and ints)
that do not allocate, we don't track them. The static allocated memory is
accounted for in a tree Node.
More discussion on this topic can be found in a review comment here:
https://codereview.chromium.org/2650943007/diff/100001/net/base/host_port_pai...

[Bence, 2017/02/02 15:05:08]

Ah okay, that makes perfect sense.  Thank you for the explanation.

+}
+
 // static
 ProxyServer ProxyServer::FromSchemeHostAndPort(
     Scheme scheme,