[fuchsia] Prepare to migrate NetInterface::flags.

This allows the flags field to be changed to a FIDL |bits| type without
breaking the Chromium build.

The |static_cast|s introduced in this change will be removed after the
next Fuchsia SDK roll.

Bug: 1099393
Change-Id: Ie0628ac0dbe7dd8dd407d5907b0ef38cbd839da8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2353295
Commit-Queue: Tamir Duberstein <tamird@google.com>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798196}

net/base/network_change_notifier_fuchsia_unittest.cc

@@ -68,7 +68,8 @@ fuchsia::netstack::NetInterface DefaultNetInterface() {
   // is sufficient.
   fuchsia::netstack::NetInterface interface;
   interface.id = kDefaultInterfaceId;
-  interface.flags = fuchsia::netstack::NetInterfaceFlagUp;
+  interface.flags = static_cast<decltype(interface.flags)>(
+      fuchsia::netstack::NetInterfaceFlagUp);
   interface.features = {};
   interface.addr = IpAddressFrom(kDefaultIPv4Address);
   interface.netmask = IpAddressFrom(kDefaultIPv4Netmask);
@@ -81,7 +82,8 @@ fuchsia::netstack::NetInterface SecondaryNetInterface() {
   // is sufficient.
   fuchsia::netstack::NetInterface interface;
   interface.id = kSecondaryInterfaceId;
-  interface.flags = fuchsia::netstack::NetInterfaceFlagUp;
+  interface.flags = static_cast<decltype(interface.flags)>(
+      fuchsia::netstack::NetInterfaceFlagUp);
   interface.features = {};
   interface.addr = IpAddressFrom(kSecondaryIPv4Address);
   interface.netmask = IpAddressFrom(kSecondaryIPv4Netmask);
@@ -507,7 +509,7 @@ TEST_F(NetworkChangeNotifierFuchsiaTest, InterfaceDown) {
   EXPECT_EQ(NetworkChangeNotifier::ConnectionType::CONNECTION_UNKNOWN,
             notifier_->GetCurrentConnectionType());
 
-  interfaces[0].flags = 0;
+  interfaces[0].flags = {};
   netstack_.SetInterfaces(interfaces);
 
   EXPECT_TRUE(type_observer_->RunAndExpectConnectionTypes(
@@ -518,14 +520,15 @@ TEST_F(NetworkChangeNotifierFuchsiaTest, InterfaceDown) {
 TEST_F(NetworkChangeNotifierFuchsiaTest, InterfaceUp) {
   std::vector<fuchsia::netstack::NetInterface> interfaces(1);
   interfaces[0] = DefaultNetInterface();
-  interfaces[0].flags = 0;
+  interfaces[0].flags = {};
 
   netstack_.SetInterfaces(interfaces);
   CreateNotifier();
   EXPECT_EQ(NetworkChangeNotifier::ConnectionType::CONNECTION_NONE,
             notifier_->GetCurrentConnectionType());
 
-  interfaces[0].flags = fuchsia::netstack::NetInterfaceFlagUp;
+  interfaces[0].flags = static_cast<decltype(interfaces[0].flags)>(
+      fuchsia::netstack::NetInterfaceFlagUp);
   netstack_.SetInterfaces(interfaces);
 
   EXPECT_TRUE(type_observer_->RunAndExpectConnectionTypes(

net/base/network_interfaces_fuchsia.cc

@@ -62,7 +62,9 @@ NetworkChangeNotifier::ConnectionType ConvertConnectionType(
     const fuchsia::netstack::NetInterface& iface) {
   auto wlan = static_cast<decltype(iface.features)>(
       fuchsia::hardware::ethernet::INFO_FEATURE_WLAN);
-  if (!(iface.flags & fuchsia::netstack::NetInterfaceFlagUp)) {
+  auto up =
+      static_cast<decltype(iface.flags)>(fuchsia::netstack::NetInterfaceFlagUp);
+  if ((iface.flags & up) != up) {
     return NetworkChangeNotifier::CONNECTION_NONE;
   } else if ((iface.features & wlan) == wlan) {
     return NetworkChangeNotifier::CONNECTION_WIFI;