[CrOS Tether] Create HostScanCache, which caches scan results and inserts them into the network sta…

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 85dc49d02f0273374185f6ff9c3f5497562de553..6ac6026f36901d3fc7662144442cc70d0cda5530 100644
--- a/chromeos/components/tether/BUILD.gn
+++ b/chromeos/components/tether/BUILD.gn
@@ -24,6 +24,8 @@ static_library("tether") {
     "connect_tethering_operation.h",
     "device_id_tether_network_guid_map.cc",
     "device_id_tether_network_guid_map.h",
+    "host_scan_cache.cc",
+    "host_scan_cache.h",
     "host_scan_device_prioritizer.cc",
     "host_scan_device_prioritizer.h",
     "host_scan_scheduler.cc",
@@ -90,6 +92,8 @@ static_library("test_support") {
     "fake_active_host.h",
     "fake_ble_connection_manager.cc",
     "fake_ble_connection_manager.h",
+    "fake_host_scan_cache.cc",
+    "fake_host_scan_cache.h",
     "fake_notification_presenter.cc",
     "fake_notification_presenter.h",
     "fake_tether_host_fetcher.cc",
@@ -129,6 +133,7 @@ source_set("unit_tests") {
     "ble_connection_manager_unittest.cc",
     "ble_scanner_unittest.cc",
     "connect_tethering_operation_unittest.cc",
+    "host_scan_cache_unittest.cc",
     "host_scan_device_prioritizer_unittest.cc",
     "host_scan_scheduler_unittest.cc",
     "host_scanner_operation_unittest.cc",