Change Cronet's "disable_ipv6" to "disable_ipv6_on_wifi"

net/dns/host_resolver.cc

Index: net/dns/host_resolver.cc
diff --git a/net/dns/host_resolver.cc b/net/dns/host_resolver.cc
index f0cd91b5787267edf28c757e4cb80929e0480f1e..88931ad26566d59d8350e1c4984bae3a99ec0386 100644
--- a/net/dns/host_resolver.cc
+++ b/net/dns/host_resolver.cc
@@ -140,6 +140,14 @@ AddressFamily HostResolver::GetDefaultAddressFamily() const {
   return ADDRESS_FAMILY_UNSPECIFIED;
 }
 
+void HostResolver::SetNoIPv6OnWifi() {
+  NOTREACHED();
+}
+
+bool HostResolver::GetNoIPv6OnWifi() {
+  return false;
+}
+
 // static
 std::unique_ptr<HostResolver> HostResolver::CreateSystemResolver(
     const Options& options,