[net] Make HostResolverImpl::OnIPAddressChange faster by removing blocking on HaveOnlyLoopbackAddre…

net/base/host_resolver_impl.h

Index: net/base/host_resolver_impl.h
diff --git a/net/base/host_resolver_impl.h b/net/base/host_resolver_impl.h
index 1b04d2ea5f1639001cb5e25604a1a2524ff7819c..7c508ed20adbe71d7cdd580d522b38285f58bb66 100644
--- a/net/base/host_resolver_impl.h
+++ b/net/base/host_resolver_impl.h
@@ -151,6 +151,7 @@ class NET_EXPORT HostResolverImpl
   class Job;
   class ProcTask;
   class IPv6ProbeJob;
+  class LoopbackProbeJob;
   class DnsTask;
   class Request;
   typedef HostCache::Key Key;
@@ -187,9 +188,6 @@ class NET_EXPORT HostResolverImpl
                       const RequestInfo& info,
                       AddressList* addresses);
 
-  // Notifies IPv6ProbeJob not to call back, and discard reference to the job.
-  void DiscardIPv6ProbeJob();
-
   // Callback from IPv6 probe activity.
   void IPv6ProbeSetDefaultAddressFamily(AddressFamily address_family);
 
@@ -251,6 +249,8 @@ class NET_EXPORT HostResolverImpl
 
   base::WeakPtrFactory<HostResolverImpl> weak_ptr_factory_;
 
+  base::WeakPtrFactory<HostResolverImpl> probe_weak_ptr_factory_;
+
   // If present, used by DnsTask and ServeFromHosts to resolve requests.
   scoped_ptr<DnsClient> dns_client_;
 
@@ -262,9 +262,6 @@ class NET_EXPORT HostResolverImpl
   // family. When false, explicit setting of address family is used.
   bool ipv6_probe_monitoring_;
 
-  // The last un-cancelled IPv6ProbeJob (if any).
-  scoped_refptr<IPv6ProbeJob> ipv6_probe_job_;
-
   // Any resolver flags that should be added to a request by default.
   HostResolverFlags additional_resolver_flags_;