Make adb_gdb work for GN builds

build/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/rules.gni")
 import("//third_party/ijar/ijar.gni")
 
 sun_tools_jar_path = "$root_gen_dir/sun_tools_jar/tools.jar"
 
 action("find_sun_tools_jar") {
@@ skipping 14 matching lines @@
 java_prebuilt("sun_tools_java") {
   jar_path = sun_tools_jar_path
   jar_dep = ":find_sun_tools_jar"
 }
 
 generate_interface_jar("android_ijar") {
   input_jar = android_sdk_jar
   output_jar = "$root_out_dir/lib.java/android.interface.jar"
 }
 
+# Copy to the lib.unstripped directory so that gdb can easily find it.
+copy("cpplib_unstripped") {
+  _soname = "libc++_shared.so"
+  sources = [
+    "${android_libcpp_root}/libs/${android_app_abi}/${_soname}",
+  ]
+  outputs = [
+    "${root_out_dir}/lib.unstripped/${_soname}",
+  ]
+}
+
 action("cpplib_stripped") {
   _strip_bin = "${android_tool_prefix}strip"
   _soname = "libc++_shared.so"
-  _input_so = "${android_libcpp_root}/libs/${android_app_abi}/${_soname}"
+  _input_so = "${root_out_dir}/lib.unstripped/${_soname}"
   _output_so = "${root_shlib_dir}/${_soname}"
 
+  deps = [
+    ":cpplib_unstripped",
+  ]
+
   script = "//build/gn_run_binary.py"
   inputs = [
     _strip_bin,
   ]
   sources = [
     _input_so,
   ]
   outputs = [
     _output_so,
   ]
 
   _rebased_strip_bin = rebase_path(_strip_bin, root_out_dir)
   _rebased_input_so = rebase_path(_input_so, root_out_dir)
   _rebased_output_so = rebase_path(_output_so, root_out_dir)
   args = [
     _rebased_strip_bin,
     "--strip-unneeded",
     "-o",
     _rebased_output_so,
     _rebased_input_so,
   ]
 }