Add android_libcpp_lib_dir gn arg

build/config/android/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/android/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/sysroot.gni")
 
 assert(is_android)
 
@@ skipping 125 matching lines @@
     "-isystem" + rebase_path(
             "$android_ndk_root/sources/cxx-stl/llvm-libc++abi/libcxxabi/include",
             root_build_dir),
     "-isystem" +
         rebase_path("$android_ndk_root/sources/android/support/include",
                     root_build_dir),
   ]
 
   defines = [ "__GNU_SOURCE=1" ]  # Necessary for clone().
   ldflags = [ "-nostdlib" ]
-  lib_dirs = [ "$android_libcpp_root/libs/$android_app_abi" ]
+  lib_dirs = [ android_libcpp_lib_dir ]
 
   # The libc++ runtime library (must come first).
   # ASan needs to dynamically link to libc++ even in static builds so
   # that it can interpose operator new.
   if (is_component_build || is_asan) {
     libs = [ "c++_shared" ]
   } else {
     libs = [ "c++_static" ]
   }
 
@@ skipping 63 matching lines @@
 
       # Avoid errors with current NDK:
       # "third_party/android_tools/ndk/toolchains/arm-linux-androideabi-4.6/prebuilt/linux-x86_64/bin/../lib/gcc/arm-linux-androideabi/4.6/include/arm_neon.h:3426:3: error: argument must be a constant"
       "-finstrument-functions-exclude-file-list=arm_neon.h",
     ]
   }
 }
 
 config("no_cygprofile_instrumentation") {
 }