Enable webrtc and most of blink and content in the Mac GN build.

content/shell/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//tools/grit/repack.gni")
 import("//tools/grit/grit_rule.gni")
 if (is_android) {
   import("//build/config/android/config.gni")
@@ skipping 441 matching lines @@
     "//ui/resources",
     "//ui/strings",
   ]
 
   sources += [ "$root_gen_dir/webkit/devtools_resources.pak" ]
   deps += [ "//content/browser/devtools:resources" ]
   output = "$root_out_dir/content_shell.pak"
 }
 
 # TODO(GYP): Figure out what this should be on android
-if (!is_android) {
+# and make linking this work on the Mac.
+if (!is_android && !is_mac) {
 
 executable("content_shell") {
   testonly = true
   # TODO(GYP) mac resource bundle stuff for this target.
   # TODO(GYP) Windows content shell settings:
   #  - Manifest.
   #  - RC file.
   #  - 'LinkIncremental': '<(msvs_large_module_debug_link_mode)',
   sources = [
     "../app/startup_helper_win.cc",
@@ skipping 21 matching lines @@
   if (is_android && !is_android_webview_build) {
     # Some tests rely on this tool. It might be nicer if these tests relied on
     # image diff rather than having content shell depend on it.
     datadeps = [
       "//tools/imagediff($host_toolchain)",
     ]
   }
 }
 
 }