[CrOS Tether]: Add LocalDeviceDataProvider, which fetches device data for the local device.

chromeos/components/tether/BUILD.gn

Index: chromeos/components/tether/BUILD.gn
diff --git a/chromeos/components/tether/BUILD.gn b/chromeos/components/tether/BUILD.gn
index e4905284901d00d6ccc0c3e50f925adc48d8674b..3de4929d509b8cd865d89943b0064ee9fedbffb5 100644
--- a/chromeos/components/tether/BUILD.gn
+++ b/chromeos/components/tether/BUILD.gn
@@ -12,6 +12,8 @@ static_library("tether") {
     "host_scanner.h",
     "initializer.cc",
     "initializer.h",
+    "local_device_data_provider.cc",
+    "local_device_data_provider.h",
   ]
 
   deps = [
@@ -46,6 +48,7 @@ source_set("unit_tests") {
 
   sources = [
     "host_scan_scheduler_unittest.cc",
+    "local_device_data_provider_unittest.cc",
   ]
 
   deps = [