Implement means to create an Environment

implement EnvironmentFactory class
and CreateEnvironment function.

Bug: webrtc:15656
Change-Id: Ib5ec0e35896be08e6125bcabc6abf2341e613909
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/328060
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41220}
diff --git a/api/BUILD.gn b/api/BUILD.gn
index e9e6887..e57092e 100644
--- a/api/BUILD.gn
+++ b/api/BUILD.gn
@@ -1484,6 +1484,7 @@
       "../test:fileutils",
       "../test:rtc_expect_death",
       "../test:test_support",
+      "environment:environment_unittests",
       "task_queue:task_queue_default_factory_unittests",
       "test/pclf:media_configuration",
       "test/video:video_frame_writer",