[CrOS Tether] Create KeepAliveScheduler, a class which schedules keep-alive tickles to be sent to a…

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 33ddb7c17e59869b25cddcc4c7742fff68603916..b1143db2f7a152a31dd1cc7906aed076dfab166a 100644
--- a/chromeos/components/tether/BUILD.gn
+++ b/chromeos/components/tether/BUILD.gn
@@ -32,6 +32,8 @@ static_library("tether") {
     "initializer.h",
     "keep_alive_operation.cc",
     "keep_alive_operation.h",
+    "keep_alive_scheduler.cc",
+    "keep_alive_scheduler.h",
     "local_device_data_provider.cc",
     "local_device_data_provider.h",
     "message_transfer_operation.cc",
@@ -64,6 +66,8 @@ static_library("test_support") {
   testonly = true
 
   sources = [
+    "fake_active_host.cc",
+    "fake_active_host.h",
     "fake_ble_connection_manager.cc",
     "fake_ble_connection_manager.h",
     "fake_tether_host_fetcher.cc",
@@ -80,6 +84,7 @@ static_library("test_support") {
     "//base",
     "//components/cryptauth",
     "//testing/gmock",
+    "//testing/gtest",
   ]
 }
 
@@ -98,6 +103,7 @@ source_set("unit_tests") {
     "host_scanner_operation_unittest.cc",
     "host_scanner_unittest.cc",
     "keep_alive_operation_unittest.cc",
+    "keep_alive_scheduler_unittest.cc",
     "local_device_data_provider_unittest.cc",
     "message_transfer_operation_unittest.cc",
     "message_wrapper_unittest.cc",