Add a debug view to the browser that allows various navigation features to be used.

mash/browser/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.
 
 import("//build/config/ui.gni")
 import("//mojo/public/mojo_application.gni")
 import("//mojo/public/mojo_application_manifest.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//tools/grit/repack.gni")
 
 source_set("lib") {
   testonly = true
   sources = [
     "browser.cc",
     "browser.h",
+    "debug_view.cc",
+    "debug_view.h",
   ]
 
   deps = [
     "//base",
     "//components/mus/public/cpp",
     "//mash/public/interfaces",
     "//mojo/public/cpp/bindings",
     "//services/catalog/public/interfaces",
     "//services/navigation/public/interfaces",
     "//services/shell/public/cpp",
@@ skipping 28 matching lines @@
   data_deps = [
     ":manifest",
     "//components/mus",
   ]
 }
 
 mojo_application_manifest("manifest") {
   application_name = "browser"
   source = "manifest.json"
 }