Add Network Quality Estimator (NQE) pref manager

net/nqe/network_id.h

Index: net/nqe/network_id.h
diff --git a/net/nqe/network_id.h b/net/nqe/network_id.h
index cf8ceac9bf77563345159aac672020b786fe7164..4620ce3bd92b9f81ad5804cf810149aba8a4368e 100644
--- a/net/nqe/network_id.h
+++ b/net/nqe/network_id.h
@@ -11,6 +11,10 @@
 #include "net/base/net_export.h"
 #include "net/base/network_change_notifier.h"
 
+namespace {
+const char kValueSeparator[] = ",";
+}
+
 namespace net {
 namespace nqe {
 namespace internal {
@@ -38,6 +42,11 @@ struct NET_EXPORT_PRIVATE NetworkID {
     return std::tie(type, id) < std::tie(other.type, other.id);
   }
 
+  std::string ToString() const {
+    return id + kValueSeparator +

[bengr, 2016/09/22 23:35:46]

It seems like overill to define kValueSeparator. I would either do:

return id + "," + ...

or 

return StringPrintf("%s,%s", id.c_str(), ...

[tbansal1, 2016/09/23 17:10:32]

The value separator is going to be used soon (in the next cl) in a different
function when reading back the prefs and deserializing it. So, it is better to
keep it in a common place, but I can remove it for now, if you feel strongly
about it.

[bengr, 2016/09/23 20:31:06]

Nah. If you're gonna use it, keep it.

[tbansal1, 2016/09/23 20:50:13]

Acknowledged.

+           NetworkChangeNotifier::ConnectionTypeToString(type);
+  }
+
   // Connection type of the network.
   NetworkChangeNotifier::ConnectionType type;