Add CSS agent for various window/widget/view attributes in devtools

components/ui_devtools/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.
 
 _inspector_protocol = "//third_party/inspector_protocol"
 import("$_inspector_protocol/inspector_protocol.gni")
 
 _protocol_generated = [
+  "CSS.cpp",
+  "CSS.h",
   "DOM.cpp",
   "DOM.h",
   "Forward.h",
   "Protocol.cpp",
   "Protocol.h",
 ]
 
 action("protocol_compatibility") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
   script = "$_inspector_protocol/CheckProtocolCompatibility.py"
@@ skipping 54 matching lines @@
     cflags += [ "/wd4800" ]  # Value forced to bool.
   }
 
   deps = [
     ":protocol_generated_sources",
     "//base",
     "//net",
     "//net:http_server",
   ]
 }