Decoupling rtc_base from apple specific code [without cyclic deps]

webrtc/pc/BUILD.gn

Index: webrtc/pc/BUILD.gn
diff --git a/webrtc/pc/BUILD.gn b/webrtc/pc/BUILD.gn
index 783fd67a554afaa0bda7028c7f30908fc91b900d..a7284b27a8ecda32bb1a851027ddae6d1f06f5b4 100644
--- a/webrtc/pc/BUILD.gn
+++ b/webrtc/pc/BUILD.gn
@@ -298,6 +298,10 @@ if (rtc_include_tests) {
     if (is_android) {
       deps += [ "//testing/android/native_test:native_test_support" ]
     }
+
+    if (is_ios || is_mac) {
+      deps += [ "../rtc_base:rtc_base_apple" ]
+    }
   }
 
   rtc_source_set("pc_test_utils") {
@@ -456,5 +460,9 @@ if (rtc_include_tests) {
 
       shard_timeout = 900
     }
+
+    if (is_ios || is_mac) {
+      deps += [ "../rtc_base:rtc_base_apple" ]
+    }
   }
 }