Revert of Move "max IPv6 networks" logic to BasicPortAllocator, and fix sorting.

webrtc/rtc_base/network.cc

Index: webrtc/rtc_base/network.cc
diff --git a/webrtc/rtc_base/network.cc b/webrtc/rtc_base/network.cc
index 26d6520e22b20712ef3f0cfe76b5053a84296f04..1f4a705db030e5b689e46b5fc460e7571e24e609 100644
--- a/webrtc/rtc_base/network.cc
+++ b/webrtc/rtc_base/network.cc
@@ -45,6 +45,11 @@
 namespace rtc {
 namespace {
 
+// Turning on IPv6 could make many IPv6 interfaces available for connectivity
+// check and delay the call setup time. kMaxIPv6Networks is the default upper
+// limit of IPv6 networks but could be changed by set_max_ipv6_networks().
+const int kMaxIPv6Networks = 5;
+
 const uint32_t kUpdateNetworksMessage = 1;
 const uint32_t kSignalNetworksMessage = 2;
 
@@ -88,7 +93,7 @@
   // TODO(mallinath) - Add VPN and Link speed conditions while sorting.
 
   // Networks are sorted last by key.
-  return a->key() < b->key();
+  return a->key() > b->key();
 }
 
 std::string AdapterTypeToString(AdapterType type) {
@@ -170,6 +175,7 @@
 
 NetworkManagerBase::NetworkManagerBase()
     : enumeration_permission_(NetworkManager::ENUMERATION_ALLOWED),
+      max_ipv6_networks_(kMaxIPv6Networks),
       ipv6_enabled_(true) {
 }
 
@@ -207,8 +213,18 @@
 }
 
 void NetworkManagerBase::GetNetworks(NetworkList* result) const {
+  int ipv6_networks = 0;
   result->clear();
-  result->insert(result->begin(), networks_.begin(), networks_.end());
+  for (Network* network : networks_) {
+    // Keep the number of IPv6 networks under |max_ipv6_networks_|.
+    if (network->prefix().family() == AF_INET6) {
+      if (ipv6_networks >= max_ipv6_networks_) {
+        continue;
+      }
+      ++ipv6_networks;
+    }
+    result->push_back(network);
+  }
 }
 
 void NetworkManagerBase::MergeNetworkList(const NetworkList& new_networks,