Android GN: Include libstdc++.so when doing a component build

build/config/android/config.gni

 # 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.
 
 # This file contains common system config stuff for the Android build.
 
 if (is_android) {
   has_chrome_android_internal =
       exec_script("//build/dir_exists.py",
                   [ rebase_path("//clank", root_build_dir) ],
@@ skipping 146 matching lines @@
   }
 
   android_tool_prefix = "$android_toolchain_root/bin/$_binary_prefix-"
   android_readelf = "${android_tool_prefix}readelf"
   android_objcopy = "${android_tool_prefix}objcopy"
   android_gdbserver =
       "$android_ndk_root/prebuilt/$android_prebuilt_arch/gdbserver/gdbserver"
 
   # libc++ stuff ---------------------------------------------------------------
 
+  android_libcpp_root = "$android_ndk_root/sources/cxx-stl/llvm-libc++"
   if (component_mode == "shared_library") {
     android_libcpp_library = "c++_shared"
   } else {
     android_libcpp_library = "c++_static"
   }
 
   # ABI ------------------------------------------------------------------------
 
   if (current_cpu == "x86") {
     android_app_abi = "x86"
   } else if (current_cpu == "arm") {
     import("//build/config/arm.gni")
     if (arm_version < 7) {
       android_app_abi = "armeabi"
     } else {
       android_app_abi = "armeabi-v7a"
     }
   } else if (current_cpu == "mipsel") {
     android_app_abi = "mips"
   } else if (current_cpu == "x64") {
     android_app_abi = "x86_64"
   } else if (current_cpu == "arm64") {
     android_app_abi = "arm64-v8a"
   } else if (current_cpu == "mips64el") {
     android_app_abi = "mips64"
   } else {
     assert(false, "Unknown Android ABI: " + current_cpu)
   }
 }