Decoupling rtc_base from apple specific code [without cyclic deps]

webrtc/voice_engine/BUILD.gn

Index: webrtc/voice_engine/BUILD.gn
diff --git a/webrtc/voice_engine/BUILD.gn b/webrtc/voice_engine/BUILD.gn
index e98a89b223ef1ed7482f8178cad8df4ac0cfc810..d74cf72fdc1c3e05cddcc38874e1ec71e147abcc 100644
--- a/webrtc/voice_engine/BUILD.gn
+++ b/webrtc/voice_engine/BUILD.gn
@@ -238,6 +238,9 @@ if (rtc_include_tests) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
+    if (is_ios || is_mac) {
+      deps += [ "../rtc_base:rtc_base_apple" ]
+    }
   }
 
   if (!is_ios) {