Split TaskQueue out into a separate build target.

webrtc/build/webrtc.gni

Index: webrtc/build/webrtc.gni
diff --git a/webrtc/build/webrtc.gni b/webrtc/build/webrtc.gni
index 788e60824c592fb38b02886ccfe3235eec09c76c..ae71188a85f2929f70e5a55ad4f0935b20ba6a48 100644
--- a/webrtc/build/webrtc.gni
+++ b/webrtc/build/webrtc.gni
@@ -58,15 +58,6 @@ declare_args() {
   rtc_include_tests = false
   rtc_restrict_logging = true
 
-  # Enable libevent task queues on platforms that support it.
-  if (is_win || is_mac || is_ios || is_nacl) {

[tommi, 2016/05/21 20:10:04]

this 'is_nacl' check is now gone.

[phoglund, 2016/05/23 08:23:32]

Please put this back, we need gn and gyp to be as similar as possible.

[tommi, 2016/05/23 15:37:19]

Done.  I restored this but left the 'is_nacl' check out.

-    rtc_enable_libevent = false
-    rtc_build_libevent = false
-  } else {
-    rtc_enable_libevent = true
-    rtc_build_libevent = true
-  }
-
   if (is_ios) {
     rtc_enable_protobuf = false
   }