Update existing uses of /wd4267 to use the GN config

pdf/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.
 
 pdf_engine = 0  # 0 PDFium
 
 static_library("pdf") {
   sources = [
     "button.h",
     "button.cc",
@@ skipping 27 matching lines @@
     "progress_control.h",
     "pdf_engine.h",
     "preview_mode_client.cc",
     "preview_mode_client.h",
     "resource.h",
     "resource_consts.h",
     "thumbnail_control.cc",
     "thumbnail_control.h",
   ]
 
+  # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+  configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
+
   if (pdf_engine == 0) {
     sources += [
       "pdfium/pdfium_api_string_buffer_adapter.cc",
       "pdfium/pdfium_api_string_buffer_adapter.h",
       "pdfium/pdfium_assert_matching_enums.cc",
       "pdfium/pdfium_engine.cc",
       "pdfium/pdfium_engine.h",
       "pdfium/pdfium_mem_buffer_file_read.cc",
       "pdfium/pdfium_mem_buffer_file_read.h",
       "pdfium/pdfium_mem_buffer_file_write.cc",
       "pdfium/pdfium_mem_buffer_file_write.h",
       "pdfium/pdfium_page.cc",
       "pdfium/pdfium_page.h",
       "pdfium/pdfium_range.cc",
       "pdfium/pdfium_range.h",
     ]
   }
 
-  if (is_win) {
-    cflags = [ "/wd4267" ]  # TODO(jschuh) size_t to int truncations.
-  }
-
   deps = [
     "//base",
     "//components/ui/zoom:ui_zoom",
     "//content/public/common",
     "//net",
     "//ppapi/cpp/private:internal_module",
     "//third_party/pdfium",
   ]
 }