Use GpuPreferences to avoid directly accessing switches in gpu related code

gpu/command_buffer/service/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/ui.gni")
 import("//third_party/protobuf/proto_library.gni")
 
 group("service") {
   if (is_component_build) {
     public_deps = [
@@ skipping 46 matching lines @@
     "gles2_cmd_clear_framebuffer.h",
     "gles2_cmd_copy_texture_chromium.cc",
     "gles2_cmd_copy_texture_chromium.h",
     "gles2_cmd_decoder.cc",
     "gles2_cmd_decoder.h",
     "gles2_cmd_decoder_autogen.h",
     "gles2_cmd_validation.cc",
     "gles2_cmd_validation.h",
     "gles2_cmd_validation_autogen.h",
     "gles2_cmd_validation_implementation_autogen.h",
+    "gpu_preferences.cc",
+    "gpu_preferences.h",
     "gpu_scheduler.cc",
     "gpu_scheduler.h",
     "gpu_state_tracer.cc",
     "gpu_state_tracer.h",
     "gpu_switches.cc",
     "gpu_switches.h",
     "gpu_tracer.cc",
     "gpu_tracer.h",
     "id_manager.cc",
     "id_manager.h",
@@ skipping 90 matching lines @@
     configs -= [ "//build/config/compiler:default_optimization" ]
     configs += [ "//build/config/compiler:optimize_max" ]
   }
 }
 
 proto_library("disk_cache_proto") {
   sources = [
     "disk_cache_proto.proto",
   ]
 }