Add an implementation of url_loader.mojom using OkHttp

third_party/okhttp/BUILD.gn

Index: third_party/okhttp/BUILD.gn
diff --git a/third_party/okhttp/BUILD.gn b/third_party/okhttp/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..d84c51cad1601da0c35ff48ad86dda1106b1917e
--- /dev/null
+++ b/third_party/okhttp/BUILD.gn
@@ -0,0 +1,17 @@
+# 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.
+
+import("//build/config/android/rules.gni")
+
+android_java_prebuilt("okio") {
+  jar_path = "okio-1.2.0.jar"
+}
+
+android_java_prebuilt("okhttp") {
+  jar_path = "okhttp-2.2.0.jar"
+
+  deps = [
+    ":okio",
+  ]
+}