Update native plugin dll for turn servers and video.

This CL was modified from work of sharifferdous@ (intern supervised by lliuu@)

BUG=webrtc:7389

Review-Url: https://codereview.webrtc.org/2987723002
Cr-Commit-Position: refs/heads/master@{#19146}
diff --git a/webrtc/examples/BUILD.gn b/webrtc/examples/BUILD.gn
index 004b9a2..655d6ff 100644
--- a/webrtc/examples/BUILD.gn
+++ b/webrtc/examples/BUILD.gn
@@ -620,6 +620,8 @@
       "unityplugin/simple_peer_connection.h",
       "unityplugin/unity_plugin_apis.cc",
       "unityplugin/unity_plugin_apis.h",
+      "unityplugin/video_observer.cc",
+      "unityplugin/video_observer.h",
     ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
@@ -637,9 +639,6 @@
       "../media:rtc_media_base",
       "../modules/video_capture:video_capture_module",
       "../pc:libjingle_peerconnection",
-      "../rtc_base:rtc_base",
-      "../rtc_base:rtc_base_approved",
-      "../rtc_base:rtc_json",
       "../system_wrappers:field_trial_default",
       "../system_wrappers:metrics_default",
     ]