[devtools] Add DOMSnapshot domain for dom+layout+style snapshots.

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 252 matching lines @@
     "public/headless_export.h",
     "public/headless_web_contents.h",
     "public/internal/message_dispatcher.h",
     "public/internal/value_conversions.h",
     "public/util/black_hole_protocol_handler.cc",
     "public/util/black_hole_protocol_handler.h",
     "public/util/deterministic_dispatcher.cc",
     "public/util/deterministic_dispatcher.h",
     "public/util/deterministic_http_protocol_handler.cc",
     "public/util/deterministic_http_protocol_handler.h",
-    "public/util/dom_tree_extractor.cc",
-    "public/util/dom_tree_extractor.h",
     "public/util/error_reporter.cc",
     "public/util/error_reporter.h",
     "public/util/expedited_dispatcher.cc",
     "public/util/expedited_dispatcher.h",
     "public/util/flat_dom_tree_extractor.cc",
     "public/util/flat_dom_tree_extractor.h",
     "public/util/generic_url_request_job.cc",
     "public/util/generic_url_request_job.h",
     "public/util/http_url_fetcher.cc",
     "public/util/http_url_fetcher.h",
@@ skipping 213 matching lines @@
   }
 }
 
 test("headless_browsertests") {
   sources = [
     "lib/frame_id_browsertest.cc",
     "lib/headless_browser_browsertest.cc",
     "lib/headless_browser_context_browsertest.cc",
     "lib/headless_devtools_client_browsertest.cc",
     "lib/headless_web_contents_browsertest.cc",
-    "public/util/dom_tree_extractor_browsertest.cc",
     "public/util/flat_dom_tree_extractor_browsertest.cc",
     "test/headless_browser_test.cc",
     "test/headless_browser_test.h",
     "test/headless_test_launcher.cc",
     "test/test_protocol_handler.cc",
     "test/test_protocol_handler.h",
     "test/test_url_request_job.cc",
     "test/test_url_request_job.h",
   ]
 
@@ skipping 185 matching lines @@
 
 executable("headless_example") {
   sources = [
     "app/headless_example.cc",
   ]
 
   deps = [
     ":headless_shell_lib",
   ]
 }