[Android] Include NestedSystemMessageHandler in gn builds of content_shell_apk.

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("//build_overrides/v8.gni")
 import("//third_party/icu/config.gni")
 
 generate_jni("content_shell_jni_headers") {
@@ skipping 100 matching lines @@
   testonly = true
   deps = [
     ":content_shell_apk_java",
     ":content_shell_apk_resources",
     ":content_shell_assets",
     ":content_shell_java",
     ":content_shell_manifest",
     ":libcontent_shell_content_view",
     "//base:base_java",
     "//content/public/android:content_java",
+    "//content/public/test/android:layouttest_java_support",
     "//media/capture/video/android:capture_java",
     "//net/android:net_java",
     "//third_party/mesa:osmesa",
     "//ui/android:ui_java",
   ]
   apk_name = "ContentShell"
   android_manifest = content_shell_manifest
   native_libs = [ "libcontent_shell_content_view.so" ]
   loadable_modules = [ "$root_out_dir/libosmesa.so" ]
 }
@@ skipping 111 matching lines @@
   testonly = true
   deps = [
     ":content_shell_java",
     "//base:base_java",
     "//content/public/android:content_java",
     "//testing/android/native_test:native_test_java",
     "//ui/android:ui_java",
   ]
   java_files = [ "browsertests/src/org/chromium/content_shell/browsertests/ContentShellBrowserTestActivity.java" ]
 }