Add TaskManagerSingleton alias

Bug: 246316711
Test: ./run_tests.sh
Change-Id: Ib563d2741ef977ed170f3d900b70783f24639252
diff --git a/platform/linux/include/chre/platform/linux/task_util/task_manager.h b/platform/linux/include/chre/platform/linux/task_util/task_manager.h
index 1197eca..9710c39 100644
--- a/platform/linux/include/chre/platform/linux/task_util/task_manager.h
+++ b/platform/linux/include/chre/platform/linux/task_util/task_manager.h
@@ -26,6 +26,7 @@
 #include "chre/platform/linux/task_util/task.h"
 #include "chre/util/non_copyable.h"
 #include "chre/util/priority_queue.h"
+#include "chre/util/singleton.h"
 
 namespace chre {
 
@@ -124,6 +125,9 @@
   std::condition_variable mConditionVariable;
 };
 
+// Provide an alias to the TaskManager singleton.
+typedef Singleton<TaskManager> TaskManagerSingleton;
+
 }  // namespace chre
 
 #endif  // CHRE_PLATFORM_LINUX_TASK_UTIL_TASK_MANAGER_H_