Allow native_viewport to create new native windows on demand on Android.

shell/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/ui.gni")
 import("//mojo/public/mojo.gni")
 import("//mojo/public/mojo_application.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//mojo/tools/embed/rules.gni")
 import("//testing/test.gni")
@@ skipping 50 matching lines @@
     shared_library("mojo_shell") {
       sources = [
         "android/library_loader.cc",
         "android/main.cc",
         "android/main.h",
       ]
 
       deps = shell_common_deps + [
                ":jni_headers",
                "//mojo/android:libsystem_java",
+               "//mojo/services/native_viewport/public/interfaces:interfaces",
                "//mojo/services/window_manager/public/interfaces:interfaces",
                "//services/native_viewport:lib",
                "//shell/application_manager",
                "//ui/gl",
              ]
 
       data_deps = shell_common_data_deps
     }
   } else {
     executable("mojo_shell") {
@@ skipping 201 matching lines @@
       "android/apk/src/org/chromium/mojo/shell/MojoShellActivity.java",
       "android/apk/src/org/chromium/mojo/shell/MojoShellApplication.java",
       "android/apk/src/org/chromium/mojo/shell/NfcApplicationDelegate.java",
       "android/apk/src/org/chromium/mojo/shell/NfcDbManager.java",
       "android/apk/src/org/chromium/mojo/shell/NfcImpl.java",
       "android/apk/src/org/chromium/mojo/shell/NfcReceiverActivity.java",
       "android/apk/src/org/chromium/mojo/shell/NfcServiceFactoryBinder.java",
       "android/apk/src/org/chromium/mojo/shell/SharingActivity.java",
       "android/apk/src/org/chromium/mojo/shell/SharingApplicationDelegate.java",
       "android/apk/src/org/chromium/mojo/shell/ShellService.java",
+      "android/apk/src/org/chromium/mojo/shell/ViewportActivity.java",
     ]
 
     deps = [
       ":resources",
       "//base:base_java",
       "//mojo/android:system_java",
       "//mojo/public/interfaces/application:application_java",
       "//mojo/public/java:application",
       "//mojo/public/java:bindings",
       "//mojo/public/java:system",
@@ skipping 298 matching lines @@
       "${root_out_dir}/libmojo_shell.so",
     ]
   } else {
     sources += [ "${root_out_dir}/mojo_shell" ]
   }
 
   outputs = [
     "${root_out_dir}/symbols/{{source_file_part}}",
   ]
 }