Change Cronet's "disable_ipv6" to "disable_ipv6_on_wifi"

net/dns/host_resolver_impl.h

Index: net/dns/host_resolver_impl.h
diff --git a/net/dns/host_resolver_impl.h b/net/dns/host_resolver_impl.h
index 24062d91ae015c5407b69b06a731ea5646a6b62f..690839e0b91e006175fcdf853f49502a9afeaa22 100644
--- a/net/dns/host_resolver_impl.h
+++ b/net/dns/host_resolver_impl.h
@@ -161,6 +161,9 @@ class NET_EXPORT HostResolverImpl
   void SetDefaultAddressFamily(AddressFamily address_family) override;
   AddressFamily GetDefaultAddressFamily() const override;
 
+  void SetNoIPv6OnWifi() override;
+  bool GetNoIPv6OnWifi() override;
+
   void set_proc_params_for_test(const ProcTaskParams& proc_params) {
     proc_params_ = proc_params;
   }
@@ -256,7 +259,11 @@ class NET_EXPORT HostResolverImpl
   // Probes IPv6 support and returns true if IPv6 support is enabled.
   // Results are cached, i.e. when called repeatedly this method returns result
   // from the first probe for some time before probing again.
-  virtual bool IsIPv6Reachable(const NetLogWithSource& net_log);
+  bool IsIPv6Reachable(const NetLogWithSource& net_log);
+
+  // Attempts to connect a UDP socket to |dest|:53. Virtual for testing.
+  virtual bool IsGloballyReachable(const IPAddress& dest,
+                                   const NetLogWithSource& net_log);
 
   // Asynchronously checks if only loopback IPs are available.
   virtual void RunLoopbackProbeJob();
@@ -353,6 +360,10 @@ class NET_EXPORT HostResolverImpl
   // http://crbug.com/696569 for why the option is needed.
   AddressFamily default_address_family_;
 
+  // True if IPv6 should not be attempted when on a WiFi connection. See
+  // https://crbug.com/696569 for further context.
+  bool assume_ipv6_failure_on_wifi_;
+
   // True if DnsConfigService detected that system configuration depends on
   // local IPv6 connectivity. Disables probing.
   bool use_local_ipv6_;