Check for use_x11 before runnig desktop_capture_modules_tests on linux.

webrtc/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")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//build/config/ui.gni")
 import("//build_overrides/build.gni")
 import("//testing/test.gni")
 
 declare_args() {
   # Disable this to avoid building the Opus audio codec.
   rtc_include_opus = true
 
   # Enable this if the Opus version upon which WebRTC is built supports direct
   # encoding of 120 ms packets.
   rtc_opus_support_120ms_ptime = false
@@ skipping 142 matching lines @@
   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
+rtc_desktop_capture_supported = is_win || is_mac || (is_linux && use_x11)
 
 ###############################################################################
 # 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 134 matching lines @@
                            ])
     configs += invoker.configs
     configs -= rtc_remove_configs
     configs -= invoker.suppressed_configs
     public_configs = [ rtc_common_inherited_config ]
     if (defined(invoker.public_configs)) {
       public_configs += invoker.public_configs
     }
   }
 }