Test default TaskQueue implementation via TaskQueueBase interface

Bug: webrtc:10191
Change-Id: I97a73311790e8ceac00d5575dd124ad8ad76503f
Reviewed-on: https://webrtc-review.googlesource.com/c/124400
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26853}
diff --git a/api/task_queue/BUILD.gn b/api/task_queue/BUILD.gn
index 578a212..e7e3aec 100644
--- a/api/task_queue/BUILD.gn
+++ b/api/task_queue/BUILD.gn
@@ -60,9 +60,7 @@
 }
 
 rtc_source_set("default_task_queue_factory") {
-  # TODO(bugs.webrtc.org/10191): Make public when implemented for all
-  # supported platforms.
-  visibility = [ ":global_task_queue_factory" ]
+  visibility = [ "*" ]
   sources = [
     "default_task_queue_factory.h",
   ]
@@ -112,6 +110,20 @@
   }
 }
 
+if (rtc_include_tests) {
+  rtc_source_set("task_queue_default_factory_unittests") {
+    testonly = true
+    sources = [
+      "default_task_queue_factory_unittest.cc",
+    ]
+    deps = [
+      ":default_task_queue_factory",
+      ":task_queue_test",
+      "../../test:test_support",
+    ]
+  }
+}
+
 # Linking with global_task_queue_factory adds link-time implementation of the
 # rtc::TaskQueue that allows run-time injection of the TaskQueue implementaion.
 rtc_source_set("global_task_queue_factory") {