Implement window management devtools commands for headless.

headless/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.
 
 import("//build/config/chrome_build.gni")
 import("//build/util/process_version.gni")
 import("//headless/headless.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//printing/features/features.gni")
 import("//testing/test.gni")
@@ skipping 112 matching lines @@
   ]
   deps = [
     ":tab_socket__generator",
   ]
 }
 
 devtools_domains = [
   "accessibility",
   "animation",
   "application_cache",
+  "browser",
   "cache_storage",
   "console",
   "css",
   "database",
   "debugger",
   "device_orientation",
   "dom",
   "dom_debugger",
   "dom_storage",
   "emulation",
@@ skipping 559 matching lines @@
 
 executable("headless_example") {
   sources = [
     "app/headless_example.cc",
   ]
 
   deps = [
     ":headless_shell_lib",
   ]
 }