Add an implementation of url_loader.mojom using OkHttp

sky/shell/BUILD.gn

 # Copyright 2015 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_android)
 
 import("//build/config/android/config.gni")
 import("//build/config/android/rules.gni")
 
 group("shell") {
@@ skipping 67 matching lines @@
     "apk/src/org/domokit/sky/shell/SkyShellApplication.java",
   ]
 
   deps = [
     "//base:base_java",
     "//mojo/android:system_java",
     "//mojo/public/interfaces/application:application_java",
     "//mojo/public/java:bindings",
     "//mojo/public/java:system",
     "//mojo/services/network/public/interfaces:interfaces_java",
+    "//sky/services/oknet",
   ]
 }
 
 sky_shell_assets_dir = "$root_build_dir/sky_shell/assets"
 
 android_resources("resources") {
   resource_dirs = [ "apk/res" ]
   custom_package = "org.domokit.sky.shell"
 }
 
@@ skipping 17 matching lines @@
   asset_location = sky_shell_assets_dir
 
   deps = [
     "//base:base_java",
     ":assets",
     ":java",
     ":resources",
     ":sky_shell",
   ]
 }