DevTools: enable private field checks as a part of compilation.

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/public/public_features.gni")
 import("//third_party/WebKit/Source/core/core.gni")
 
 devtools_embedder_scripts = [
   "front_end/devtools_compatibility.js",
@@ skipping 494 matching lines @@
   "front_end/gonzales/SCSSParser.js",
 ]
 devtools_heap_snapshot_worker_js_files = [
   "front_end/common/TextUtils.js",
   "front_end/common/UIString.js",
   "front_end/heap_snapshot_worker/AllocationProfile.js",
   "front_end/heap_snapshot_worker/HeapSnapshot.js",
   "front_end/heap_snapshot_worker/HeapSnapshotLoader.js",
   "front_end/heap_snapshot_worker/HeapSnapshotWorker.js",
   "front_end/heap_snapshot_worker/HeapSnapshotWorkerDispatcher.js",
-  "front_end/heap_snapshot_worker/JSHeapSnapshot.js",
   "front_end/platform/utilities.js",
   "front_end/profiler/HeapSnapshotCommon.js",
 ]
 devtools_layers_js_files = [
   "front_end/layers/LayerPaintProfilerView.js",
   "front_end/layers/LayerTreeModel.js",
   "front_end/layers/LayersPanel.js",
 ]
 devtools_network_js_files = [
   "front_end/network/blockedURLsPane.css",
@@ skipping 665 matching lines @@
     ".eslintrc.js",
     "devtools-node-modules/",
     "front_end/",
     "scripts/buildbot/run_eslint.py",
     "scripts/local_node/",
     "//testing/scripts/common.py",
     "//testing/scripts/run_devtools_check.py",
     "//testing/xvfb.py",
   ]
 }