NetworkStateHandler: Ignore updates before initial properties received

This CL ignores Device PropertyChanged updates sent before the initial
GetProperties request is received. It fixes an edge case triggering a
DCHECK when the |type| property is not set yet (it is set when the
initial properties are received).

Bug: 1008193
Change-Id: I1a32578ba8a9f5ae7deda53c27c9c2fc8556e0b3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1836178Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702482}

chromeos/network/network_state_handler.cc

@@ -1431,8 +1431,12 @@ void NetworkStateHandler::UpdateDeviceProperty(const std::string& device_path,
                                                const base::Value& value) {
   SCOPED_NET_LOG_IF_SLOW();
   DeviceState* device = GetModifiableDeviceState(device_path);
-  if (!device)
+  if (!device || !device->update_received()) {
+    // Shill may send a device property update before processing Chrome's
+    // initial GetProperties request. If this occurs, the initial request will
+    // include the changed property value so we can ignore this update.
     return;
+  }
   if (!device->PropertyChanged(key, value))
     return;