Remove enable_vulkan from build/config, and move it to the buildflag_header system.

cc/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("//cc/cc.gni")
+import("//gpu/vulkan/features.gni")
 
 cc_component("cc") {
   sources = [
     "debug/benchmark_instrumentation.cc",
     "debug/benchmark_instrumentation.h",
     "debug/debug_colors.cc",
     "debug/debug_colors.h",
     "debug/debug_rect_history.cc",
     "debug/debug_rect_history.h",
     "debug/devtools_instrumentation.cc",
@@ skipping 507 matching lines @@
   deps = [
     "//base",
     "//base/third_party/dynamic_annotations",
     "//cc/paint",
     "//cc/surfaces:surface_id",
     "//gpu",
     "//gpu/command_buffer/client:gles2_implementation",
     "//gpu/command_buffer/client:gles2_interface",
     "//gpu/ipc:gl_in_process_context",
     "//gpu/skia_bindings:skia_bindings",
+    "//gpu/vulkan:features",
     "//media",
     "//mojo/public/cpp/bindings:struct_traits",
     "//third_party/libyuv",
     "//ui/events:events_base",
     "//ui/gfx",
     "//ui/gfx/geometry",
     "//ui/gl",
   ]
 
   defines = [ "CC_IMPLEMENTATION=1" ]
@@ skipping 454 matching lines @@
   data = [
     "test/data/",
 
     # Needed for isolate script to execute.
     "//testing/scripts/common.py",
     "//testing/xvfb.py",
     "//testing/scripts/run_gtest_perf_test.py",
     "//tools/perf/generate_legacy_perf_dashboard_json.py",
   ]
 }