Revert of GN: Add BUILD.gn files for webrtc/{api,media,libjingle,p2p,pc}

webrtc/BUILD.gn

Index: webrtc/BUILD.gn
diff --git a/webrtc/BUILD.gn b/webrtc/BUILD.gn
index 37f74dd47b1aa81a4fbb30055848df47bdb2f596..07f2fe998d37982aaa5a626c3c50bd1abf8bf37a 100644
--- a/webrtc/BUILD.gn
+++ b/webrtc/BUILD.gn
@@ -111,10 +111,6 @@
     # build/config/linux/pkg-config.py dbus-glib-1 returns correct include
     # dirs on Linux.
     all_dependent_configs = [ "dbus-glib" ]
-  }
-
-  if (rtc_relative_path) {
-    defines += [ "EXPAT_RELATIVE_PATH" ]
   }
 
   if (build_with_chromium) {
@@ -237,13 +233,11 @@
 
   deps = [
     ":webrtc_common",
-    "api",
     "audio",
     "base:rtc_base",
     "call",
     "common_audio",
     "common_video",
-    "media",
     "modules/audio_coding",
     "modules/audio_conference_mixer",
     "modules/audio_device",
@@ -255,8 +249,6 @@
     "modules/utility",
     "modules/video_coding",
     "modules/video_processing",
-    "p2p",
-    "pc",
     "system_wrappers",
     "tools",
     "video",