Add warmup and sandbox file-read permission for testing

third_party/WebKit/Source/modules/shapedetection/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.
 
 import("//third_party/WebKit/Source/modules/modules.gni")
 
 blink_modules_sources("shapedetection") {
   sources = [
     "DetectedFace.cpp",
     "DetectedFace.h",
     "FaceDetector.cpp",
     "FaceDetector.h",
+    "FaceDetectorImpl.h",
+    "FaceDetectorImplMac.h",
+    "FaceDetectorImplMac.mm",
   ]
 }