Update existing uses of /wd4267 to use the GN config

webkit/common/gpu/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.
 
 # GYP version: webkit/common/gpu/webkit_gpu.gyp:webkit_gpu
 component("gpu") {
   output_name = "webkit_gpu"
 
   sources = [
     "context_provider_in_process.cc",
     "context_provider_in_process.h",
     "context_provider_web_context.h",
     "grcontext_for_webgraphicscontext3d.cc",
     "grcontext_for_webgraphicscontext3d.h",
   ]
 
   defines = [ "WEBKIT_GPU_IMPLEMENTATION" ]
-  configs += [ "//build/config/compiler:wexit_time_destructors" ]
-  if (is_win) {
+  configs += [
+    "//build/config/compiler:wexit_time_destructors",
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-    cflags = [ "/wd4267" ]
-  }
+    "//build/config/compiler:no_size_t_to_int_warning",
+  ]
 
   deps = [
     "//base",
     "//base/third_party/dynamic_annotations",
     "//cc",
     "//gpu/blink",
     "//gpu/command_buffer/common",
     "//gpu/command_buffer/service",
     "//gpu/command_buffer/client:gles2_c_lib",
     "//gpu/command_buffer/client:gles2_implementation",
     "//gpu/command_buffer/client:gl_in_process_context",
     "//gpu/skia_bindings",
     "//skia",
     "//third_party/WebKit/public:blink_minimal",
     "//third_party/angle:translator",
     "//ui/gl",
     "//ui/gfx",
     "//ui/gfx/geometry",
   ]
 }