Enable Popular Sites in Android demo mode.

components/ntp_tiles/BUILD.gn

 # Copyright 2016 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.
 
 assert(!is_ios)  # TODO(sfiera): support iOS http://crbug.com/617966
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
@@ skipping 19 matching lines @@
   ]
   deps = [
     "//components/google/core/browser",
     "//components/pref_registry",
     "//components/prefs",
     "//components/safe_json",
     "//components/search_engines",
     "//components/variations",
     "//components/variations/service",
   ]
+
+  if (is_android) {
+    deps += [ "android:ntp_tiles_jni_headers" ]
+  }
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "most_visited_sites_unittest.cc",
   ]
 
   deps = [
     ":ntp_tiles",
     "//testing/gtest",
   ]
 }
 
 if (is_android) {
   java_cpp_enum("ntp_tiles_enums_java") {
     sources = [
       "most_visited_sites.h",
     ]
   }
 }