Enable external V8 snapshot on Android through GN.

content/shell/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/config.gni")
 import("//build/config/android/rules.gni")
 import("//third_party/icu/config.gni")
 
 generate_jni("content_shell_jni_headers") {
   jni_package = "content/shell"
@@ skipping 76 matching lines @@
   dest = content_shell_assets_dir
   sources = [
     "$root_out_dir/content_shell.pak"
   ]
 
   if (icu_use_data_file) {
     sources += [
       "$root_build_dir/icudtl.dat"
     ]
   }
+  if (v8_use_external_startup_data) {
+    sources += [
+      "$root_gen_dir/natives_blob.bin",
+      "$root_gen_dir/snapshot_blob.bin",
+    ]
+  }
 }
 
 android_apk("content_shell_apk") {
   use_chromium_linker = true
   testonly = true
   datadeps = [
     # "//tools/android/forwarder",
   ]
   deps = [
     ":content_shell_apk_resources",
@@ skipping 101 matching lines @@
 
   # GYP: //content/content_tests.gypi:chromium_android_linker_test_jni_headers
   generate_jni("linker_test_jni_headers") {
     testonly = true
     jni_package = "content/shell"
     sources = [
       "linker_test_apk/src/org/chromium/chromium_linker_test_apk/LinkerTests.java",
     ]
   }
 }