GN: Fix errors when some variables are set to non-default values.

webrtc/media/BUILD.gn

 # Copyright (c) 2016 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/linux/pkg_config.gni")
 import("../build/webrtc.gni")
@@ skipping 123 matching lines @@
   }
 
   if (is_win) {
     cflags = [
       "/wd4245",  # conversion from "int" to "size_t", signed/unsigned mismatch.
       "/wd4267",  # conversion from "size_t" to "int", possible loss of data.
       "/wd4389",  # signed/unsigned mismatch.
     ]
   }
 
+  include_dirs = []
   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" ]
   }
 
   if (rtc_build_usrsctp) {
-    include_dirs = [
+    include_dirs += [
       # TODO(jiayl): move this into the public_configs of
       # //third_party/usrsctp/BUILD.gn.
       "//third_party/usrsctp/usrsctplib",
     ]
     deps += [ "//third_party/usrsctp" ]
   }
 
   if (build_with_chromium) {
     deps += [ "../modules/video_capture:video_capture" ]
   } else {
@@ skipping 49 matching lines @@
     # adds -Wall, and this flag have to be after -Wall -- so they need to
     # come from a config and can"t be on the target directly.
     if (is_clang && is_ios) {
       cflags = [ "-Wno-unused-variable" ]
     }
   }
 
   source_set("rtc_unittest_main") {
     testonly = true
 
+    include_dirs = []
+    public_deps = []
     deps = []
     sources = [
       "base/fakemediaengine.h",
       "base/fakenetworkinterface.h",
       "base/fakertp.h",
       "base/fakevideocapturer.h",
       "base/fakevideorenderer.h",
       "base/test/mock_mediachannel.h",
       "base/testutils.cc",
       "base/testutils.h",
       "engine/fakewebrtccall.cc",
       "engine/fakewebrtccall.h",
       "engine/fakewebrtccommon.h",
       "engine/fakewebrtcdeviceinfo.h",
       "engine/fakewebrtcvcmfactory.h",
       "engine/fakewebrtcvideocapturemodule.h",
       "engine/fakewebrtcvideoengine.h",
       "engine/fakewebrtcvoiceengine.h",
     ]
 
     configs += [
       "..:common_config",
       ":rtc_unittest_main_config",
     ]
     public_configs = [ "..:common_inherited_config" ]
 
     if (rtc_build_libyuv) {
       deps += [ "$rtc_libyuv_dir" ]
-      public_deps = [
-        "$rtc_libyuv_dir",
-      ]
+      public_deps += [ "$rtc_libyuv_dir" ]
     } else {
       # Need to add a directory normally exported by libyuv.
       include_dirs += [ "$rtc_libyuv_dir/include" ]
     }
 
     if (is_clang) {
       # Suppress warnings from the Chromium Clang plugin.
       # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
       configs -= [ "//build/config/clang:find_bad_constructs" ]
     }
@@ skipping 90 matching lines @@
     deps += [
       # TODO(kjellander): Move as part of work in bugs.webrtc.org/4243.
       ":rtc_media",
       ":rtc_unittest_main",
       "../audio",
       "../base:rtc_base_tests_utils",
       "../system_wrappers:metrics_default",
     ]
   }
 }