[DevTools] Migrate RequestHeadersView to TreeOutlineInShadow.

third_party/WebKit/Source/devtools/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("//third_party/WebKit/Source/core/core.gni")
 
 devtools_embedder_scripts = [
   "front_end/devtools.js",
   "front_end/Tests.js",
@@ skipping 489 matching lines @@
   "front_end/layers/LayersPanel.js",
 ]
 devtools_network_js_files = [
   "front_end/network/blockedURLsPane.css",
   "front_end/network/eventSourceMessagesView.css",
   "front_end/network/networkConfigView.css",
   "front_end/network/networkLogView.css",
   "front_end/network/networkManageCustomHeadersView.css",
   "front_end/network/networkPanel.css",
   "front_end/network/requestCookiesView.css",
+  "front_end/network/requestHeadersTree.css",
   "front_end/network/requestHeadersView.css",
   "front_end/network/webSocketFrameView.css",
   "front_end/network/xmlView.css",
   "front_end/network/BlockedURLsPane.js",
   "front_end/network/EventSourceMessagesView.js",
   "front_end/network/FilterSuggestionBuilder.js",
   "front_end/network/HARWriter.js",
   "front_end/network/JSONView.js",
   "front_end/network/NetworkConfigView.js",
   "front_end/network/NetworkDataGridNode.js",
@@ skipping 637 matching lines @@
     ]
   }
 
   copy("copy_emulated_devices_images_debug") {
     sources = devtools_emulated_devices_images
     outputs = [
       "$resources_out_debug_dir/emulated_devices/{{source_file_part}}",
     ]
   }
 }