Decoupling rtc_base from apple specific code [without cyclic deps]

webrtc/modules/rtp_rtcp/BUILD.gn

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("../../webrtc.gni")
 
@@ skipping 222 matching lines @@
     sources = [
       "test/testFec/average_residual_loss_xor_codes.h",
       "test/testFec/test_packet_masks_metrics.cc",
     ]
 
     deps = [
       ":rtp_rtcp",
       "../../test:test_main",
       "//testing/gtest",
     ]
+
+    if (is_ios) {
+      deps += [ "../../rtc_base:rtc_base_apple" ]
+    }
   }  # test_packet_masks_metrics
 
   rtc_source_set("rtp_rtcp_modules_tests") {
     testonly = true
 
     # Skip restricting visibility on mobile platforms since the tests on those
     # gets additional generated targets which would require many lines here to
     # cover (which would be confusing to read and hard to maintain).
     if (!is_android && !is_ios) {
       visibility = [ "../../modules:modules_tests" ]
@@ skipping 100 matching lines @@
     ]
 
     # TODO(jschuh): bugs.webrtc.org/1348: fix this warning.
     configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 }