Decoupling rtc_base from apple specific code [without cyclic deps]

webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn

Index: webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn
diff --git a/webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn b/webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn
index af24f8ab5e477c0af660460dcf4b1fb6924d75b8..cc10bbcb9b3a9a90a6512ea64ae3b3a294b6306d 100644
--- a/webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn
+++ b/webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn
@@ -26,6 +26,9 @@ rtc_executable("conversational_speech_generator") {
     "../../../../../webrtc/test:test_support",
     "//third_party/gflags",
   ]
+  if (is_ios) {
+    deps += [ "../../../../rtc_base:rtc_base_apple" ]
+  }
 }
 
 rtc_static_library("lib") {