android: Hide JNI exports by default.

build/config/BUILDCONFIG.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.
 
 # =============================================================================
 # BUILD FLAGS
 # =============================================================================
 #
 # This block lists input arguments to the build, along with their default
 # values. GN requires listing them explicitly so it can validate input and have
@@ skipping 423 matching lines @@
   configs = _native_compiler_configs
 }
 
 # Shared library defaults (also for components in component mode).
 _shared_library_configs =
     _native_compiler_configs + [ "//build/config:default_libs" ]
 if (is_win) {
   _shared_library_configs += _windows_linker_configs
 } else if (is_mac) {
   _shared_library_configs += [ "//build/config/mac:mac_dynamic_flags" ]
+} else if (is_android) {
+  # Strip native JNI exports from shared libraries by default. Binaries that
+  # want this can remove this config.
+  _shared_library_configs +=
+      [ "//build/config/android:hide_native_jni_exports" ]
 }
 set_defaults("shared_library") {
   configs = _shared_library_configs
 }
 if (is_component_build) {
   set_defaults("component") {
     configs = _shared_library_configs
   }
 }
 
@@ skipping 261 matching lines @@
       }
       if (defined(invoker.testonly)) {
         testonly = invoker.testonly
       }
       if (defined(invoker.visibility)) {
         visibility = invoker.visibility
       }
     }
   }
 }