Fix iOS GN build and cleanup system_wrappers

webrtc/modules/video_coding/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("../../build/webrtc.gni")
 
@@ skipping 133 matching lines @@
     # Suppress warnings from Chrome's Clang plugins.
     # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
     configs -= [ "//build/config/clang:find_bad_constructs" ]
   }
 
   defines = []
   deps = [
     "../../system_wrappers",
   ]
 
+  if (is_ios) {
+    sources += [ "codecs/h264/h264_objc.mm" ]
+    deps += [ ":webrtc_h264_video_toolbox" ]
+  }
+
   if (rtc_use_h264) {
     defines += [ "WEBRTC_USE_H264" ]
     if (rtc_initialize_ffmpeg) {
       defines += [ "WEBRTC_INITIALIZE_FFMPEG" ]
     }
     sources += [
       "codecs/h264/h264_decoder_impl.cc",
       "codecs/h264/h264_decoder_impl.h",
       "codecs/h264/h264_encoder_impl.cc",
       "codecs/h264/h264_encoder_impl.h",
     ]
     deps += [
       "../../common_video",
       "//third_party/ffmpeg:ffmpeg",
       "//third_party/openh264:encoder",
     ]
   }
 }
 
-# TODO(tkchin): Source set for webrtc_h264_video_toolbox. Currently not
-# possible to add, see https://crbug.com/297668.
+if (is_ios) {
+  source_set("webrtc_h264_video_toolbox") {
+    sources = [
+      "codecs/h264/h264_video_toolbox_decoder.cc",
+      "codecs/h264/h264_video_toolbox_decoder.h",
+      "codecs/h264/h264_video_toolbox_encoder.cc",
+      "codecs/h264/h264_video_toolbox_encoder.h",
+      "codecs/h264/h264_video_toolbox_nalu.cc",
+      "codecs/h264/h264_video_toolbox_nalu.h",
+    ]
+
+    configs += [ "//build/config/compiler:enable_arc" ]
+
+    cflags = [ "-Wobjc-missing-property-synthesis" ]
+
+    precompiled_header = "../../sdk/objc/WebRTC-Prefix.pch"
+    precompiled_source = "../../sdk/objc/WebRTC-Prefix.pch"
+
+    deps = [
+      "../../sdk:rtc_sdk_common_objc",
+    ]
+
+    libs = [
+      "CoreFoundation.framework",
+      "CoreMedia.framework",
+      "CoreVideo.framework",
+      "VideoToolbox.framework",
+    ]
+
+    if (is_clang) {
+      # Suppress warnings from Chrome's Clang plugins.
+      # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
+      configs -= [ "//build/config/clang:find_bad_constructs" ]
+    }
+
+    if (rtc_build_libyuv) {
+      deps += [ "$rtc_libyuv_dir" ]
+      public_deps = [
+        "$rtc_libyuv_dir",
+      ]
+    } else {
+      # Need to add a directory normally exported by libyuv.
+      include_dirs += [ "$rtc_libyuv_dir/include" ]
+    }
+  }
+}
 
 source_set("webrtc_i420") {
   sources = [
     "codecs/i420/i420.cc",
     "codecs/i420/include/i420.h",
   ]
 
   configs += [ "../..:common_config" ]
   public_configs = [ "../..:common_inherited_config" ]
 
@@ skipping 75 matching lines @@
 
   deps = [
     ":video_coding_utility",
     "../../common_video",
     "../../system_wrappers",
   ]
   if (rtc_build_libvpx) {
     deps += [ rtc_libvpx_dir ]
   }
 }