Use thumb versions of external libraries with ARMv7.

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 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")
 if (cpu_arch == "arm") {
   import("//build/config/arm.gni")
 }
 if (is_posix) {
   import("//build/config/gcc/gcc_version.gni")
@@ skipping 465 matching lines @@
     # Think of them like system headers, but don't use '-isystem' because the
     # arm-linux-androideabi-4.4.3 toolchain (circa Gingerbread) will exhibit
     # strange errors. The include ordering here is important; change with
     # caution.
     android_stlport_root = "$android_ndk_root/sources/cxx-stl/stlport"
 
     cflags += [
       "-isystem" + rebase_path("$android_stlport_root/stlport",
                                root_build_dir)
     ]
-    lib_dirs += [ "$android_stlport_root/libs/$android_app_abi" ]
+    if (arm_use_thumb) {
+      lib_dirs += [ "$android_stlport_root/libs/$android_app_abi/thumb" ]
+    } else {
+      lib_dirs += [ "$android_stlport_root/libs/$android_app_abi" ]
+    }
 
     if (component_mode == "shared_library") {
       libs += [ "stlport_shared" ]
     } else {
       libs += [ "stlport_static" ]
     }
 
     if (cpu_arch == "mipsel") {
       libs += [
         # ld linker is used for mips Android, and ld does not accept library
@@ skipping 455 matching lines @@
       cflags += [ "-gsplit-dwarf" ]
     }
   }
 }
 
 config("no_symbols") {
   if (!is_win) {
     cflags = [ "-g0" ]
   }
 }