NetworkStateHandler: Avoid Matches call to uninitialized networks

Briefly: When a ManagedState entry is added to a list, no initial
properties have been received, so these entries are *mostly* ignored.

In NetworkTypePattern::Matches(), we have a DCHECK to help ensure that
uninitialized states are not used. That means that when we are
iterating through a list of networks, we need to avoid calling
Matches on ManagedState.type_.

This adds a convenience wrapper for places where we need this extra
test, and uses it in UpdateManagedList which is currently triggering
DCHECKs.

TBR=vecore@chromium.org

Bug: 1049808
Change-Id: I1a159622adb24b221849e1fa1a98ce89a3357744
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2050759
Auto-Submit: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741121}

chromeos/network/network_state_handler.cc

@@ -90,6 +90,13 @@ bool ShouldIncludeNetworkInList(const NetworkState* network_state,
   return true;
 }
 
+// ManagedState entries may not have |type| set when the network is initially
+// added to a list (i.e. before the initial properties are received). Use this
+// wrapper anyplace where |managed| might be uninitialized.
+bool TypeMatches(const ManagedState* managed, const NetworkTypePattern& type) {
+  return !managed->type().empty() && managed->Matches(type);
+}
+
 }  // namespace
 
 // Class for tracking properties that affect whether a NetworkState is active.
@@ -966,7 +973,7 @@ void NetworkStateHandler::EnsureTetherDeviceState() {
 }
 
 bool NetworkStateHandler::UpdateBlockedByPolicy(NetworkState* network) const {
-  if (network->type().empty() || !network->Matches(NetworkTypePattern::WiFi()))
+  if (!TypeMatches(network, NetworkTypePattern::WiFi()))
     return false;
 
   bool prev_blocked_by_policy = network->blocked_by_policy();
@@ -1270,11 +1277,11 @@ void NetworkStateHandler::UpdateManagedList(ManagedState::ManagedType type,
   // Remove associations Tether NetworkStates had with now removed Wi-Fi
   // NetworkStates.
   for (auto& iter : managed_map) {
-    if (!iter.second->Matches(NetworkTypePattern::WiFi()))
+    ManagedState* managed = iter.second.get();
+    if (!TypeMatches(managed, NetworkTypePattern::WiFi()))
       continue;
-
     NetworkState* tether_network = GetModifiableNetworkStateFromGuid(
-        iter.second->AsNetworkState()->tether_guid());
+        managed->AsNetworkState()->tether_guid());
     if (tether_network)
       tether_network->set_tether_guid(std::string());
   }
@@ -1814,9 +1821,7 @@ DeviceState* NetworkStateHandler::GetModifiableDeviceState(
 DeviceState* NetworkStateHandler::GetModifiableDeviceStateByType(
     const NetworkTypePattern& type) const {
   for (const auto& device : device_list_) {
-    if (device->type().empty())
-      continue;  // kTypeProperty not set yet, skip.
-    if (device->Matches(type))
+    if (TypeMatches(device.get(), type))
       return device->AsDeviceState();
   }
   return nullptr;