Reland of Android: Use linker script to hide all non-JNI symbols

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.
 
 # =============================================================================
 # WHAT IS THIS FILE?
 # =============================================================================
 #
 # This is the master GN build configuration. This file is loaded after the
 # build args (args.gn) for the build directory and after the toplevel ".gn"
@@ skipping 550 matching lines @@
 
 # Shared library and loadable module defaults (also for components in component
 # mode).
 default_shared_library_configs = default_compiler_configs + [
                                    "//build/config:default_libs",
                                    "//build/config:shared_library_config",
                                  ] + _linker_configs
 if (is_android) {
   # Strip native JNI exports from shared libraries by default. Binaries that
   # want this can remove this config.
-  default_shared_library_configs += [
-    "//build/config/android:hide_native_jni_exports",
-    "//build/config/android:hide_all_but_jni_onload",
-  ]
+  default_shared_library_configs +=
+      [ "//build/config/android:hide_all_but_jni_onload" ]
 }
 set_defaults("shared_library") {
   configs = default_shared_library_configs
 }
 set_defaults("loadable_module") {
   configs = default_shared_library_configs
+
+  # loadable_modules are generally used by other libs, not just via JNI.
+  if (is_android) {
+    configs -= [ "//build/config/android:hide_all_but_jni_onload" ]
+  }
 }
 
 # ==============================================================================
 # COMPONENT SETUP
 # ==============================================================================
 
 # Defines a component, which equates to a shared_library when
 # is_component_build == true and a static_library otherwise.
 #
 # Use static libraries for the static build rather than source sets because
@@ skipping 51 matching lines @@
     }
     deps += [ "//build/config/sanitizers:deps" ]
   }
 }
 
 # Component defaults
 set_defaults("component") {
   if (is_component_build) {
     configs = default_shared_library_configs
     if (is_android) {
-      configs -= [
-        "//build/config/android:hide_native_jni_exports",
-        "//build/config/android:hide_all_but_jni_onload",
-      ]
+      configs -= [ "//build/config/android:hide_all_but_jni_onload" ]
     }
   } else {
     configs = default_compiler_configs
   }
 }