Add ash devtools client

ash/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/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//ui/base/ui_features.gni")
 
 assert(use_aura)
@@ skipping 60 matching lines @@
     "common/ash_constants.cc",
     "common/ash_constants.h",
     "common/ash_layout_constants.cc",
     "common/ash_layout_constants.h",
     "common/ash_switches.cc",
     "common/ash_switches.h",
     "common/cast_config_delegate.cc",
     "common/cast_config_delegate.h",
     "common/default_accessibility_delegate.cc",
     "common/default_accessibility_delegate.h",
+    "common/devtools/devtools_dom_agent.cc",
+    "common/devtools/devtools_dom_agent.h",
     "common/drag_drop/drag_image_view.cc",
     "common/drag_drop/drag_image_view.h",
     "common/focus_cycler.cc",
     "common/focus_cycler.h",
     "common/frame/caption_buttons/caption_button_types.h",
     "common/frame/caption_buttons/frame_caption_button.cc",
     "common/frame/caption_buttons/frame_caption_button.h",
     "common/frame/caption_buttons/frame_caption_button_container_view.cc",
     "common/frame/caption_buttons/frame_caption_button_container_view.h",
     "common/frame/caption_buttons/frame_size_button.cc",
@@ skipping 756 matching lines @@
     "//ash/public/interfaces",
     "//ash/touch_hud",
     "//base",
     "//base:i18n",
     "//base/third_party/dynamic_annotations",
     "//cc",
     "//components/device_event_log",
     "//components/onc",
     "//components/session_manager:base",
     "//components/signin/core/account_id",
+    "//components/ui_devtools",

[sky, 2016/10/28 21:27:10]

What are all the dependencies of this? I want to make sure we don't end up
pulling in content/blink. How many additional build files do this pull in?

[Sarmad Hashmi, 2016/10/28 21:58:19]

Dependencies are base, net, net:http_server, and an action which generates the
protocol using files from here:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/platform/inspe...

     "//components/user_manager",
     "//components/wallpaper",
     "//media",
     "//net",
     "//services/service_manager/public/cpp",
     "//skia",
     "//third_party/icu",
     "//ui/accessibility",
     "//ui/app_list/presenter",
     "//ui/aura",
@@ skipping 618 matching lines @@
   if (is_win) {
     configs -= [ "//build/config/win:console" ]
     configs += [ "//build/config/win:windowed" ]
     deps += [ "//sandbox" ]
   }
 
   if (is_chromeos) {
     deps += [ "//device/bluetooth" ]
   }
 }