Improve performance of proxy resolver by tracing DNS dependencies.

net/http/http_network_transaction_spdy2_unittest.cc

Index: net/http/http_network_transaction_spdy2_unittest.cc
diff --git a/net/http/http_network_transaction_spdy2_unittest.cc b/net/http/http_network_transaction_spdy2_unittest.cc
index 62d5b9d98902e0394577f321074ea7397979b115..8cabc0774eabeb64950658f757307ebf6ea9d8e4 100644
--- a/net/http/http_network_transaction_spdy2_unittest.cc
+++ b/net/http/http_network_transaction_spdy2_unittest.cc
@@ -7555,12 +7555,6 @@ class CapturingProxyResolver : public ProxyResolver {
     return LOAD_STATE_IDLE;
   }
 
-  virtual LoadState GetLoadStateThreadSafe(
-      RequestHandle request) const OVERRIDE {
-    NOTREACHED();
-    return LOAD_STATE_IDLE;
-  }
-
   virtual void CancelSetPacScript() {
     NOTREACHED();
   }