GN: Refactor modules_unittests to eliminate package boundary violations.

webrtc/build/webrtc.gni

 # 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/config/arm.gni")
 import("//build/config/features.gni")
@@ skipping 149 matching lines @@
   # Include tests in standalone checkout.
   rtc_include_tests = !build_with_chromium
 }
 
 # Make it possible to provide custom locations for some libraries (move these
 # up into declare_args should we need to actually use them for the GN build).
 rtc_libvpx_dir = "//third_party/libvpx"
 rtc_libyuv_dir = "//third_party/libyuv"
 rtc_opus_dir = "//third_party/opus"
 
+# Desktop capturer is supported only on Windows, OSX and Linux.
+rtc_desktop_capture_supported = is_win || is_mac || is_linux
+
 ###############################################################################
 # Templates
 #
 
 # Points to //webrtc/ in webrtc stand-alone or to //third_party/webrtc/ in
 # chromium.
 # We need absolute paths for all configs in templates as they are shared in
 # different subdirectories.
 webrtc_root = get_path_info("../", "abspath")
 
@@ skipping 166 matching lines @@
       _rebased_sources = rebase_path(invoker.sources, root_build_dir)
 
       args = [ "--srcjar=$_rebased_srcjar_path" ] + _rebased_sources
 
       outputs = [
         _srcjar_path,
       ]
     }
   }
 }