Improve performance of proxy resolver by tracing DNS dependencies.

net/http/http_network_transaction_spdy3_unittest.cc

Index: net/http/http_network_transaction_spdy3_unittest.cc
diff --git a/net/http/http_network_transaction_spdy3_unittest.cc b/net/http/http_network_transaction_spdy3_unittest.cc
index 03a2c8ed4682f3fb6229db2ebeb68de1a7e6fac8..ff54dadc64938e3bf8624e90f34517c5dd409f9d 100644
--- a/net/http/http_network_transaction_spdy3_unittest.cc
+++ b/net/http/http_network_transaction_spdy3_unittest.cc
@@ -8083,12 +8083,6 @@ class CapturingProxyResolver : public ProxyResolver {
     return LOAD_STATE_IDLE;
   }
 
-  virtual LoadState GetLoadStateThreadSafe(
-      RequestHandle request) const OVERRIDE {
-    NOTREACHED();
-    return LOAD_STATE_IDLE;
-  }
-
   virtual void CancelSetPacScript() {
     NOTREACHED();
   }