GN: Fix incorrect include_dir for libjingle_peerconnection_jni target

webrtc/api/BUILD.gn

 # Copyright (c) 2015 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")
 if (is_android) {
@@ skipping 199 matching lines @@
       "../system_wrappers:metrics_default",
     ]
 
     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 += [ "$rtc_libyuv_dir/include" ]
+      include_dirs = [ "$rtc_libyuv_dir/include" ]
     }
   }
 
   rtc_shared_library("libjingle_peerconnection_so") {
     sources = [
       "android/jni/jni_onload.cc",
     ]
 
     suppressed_configs += [ "//build/config/android:hide_native_jni_exports" ]
 
@@ skipping 233 matching lines @@
 
       shared_libraries = [ ":libjingle_peerconnection_so" ]
     }
 
     android_resources("libjingle_peerconnection_android_unittest_resources") {
       resource_dirs = [ "androidtests/res" ]
       custom_package = "org.webrtc"
     }
   }
 }