Fix various flags in the Win64 GN build

base/BUILD.gn

 # Copyright (c) 2013 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")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
@@ skipping 1385 matching lines @@
   }
 
   if (is_android) {
     deps += [
       "//testing/android:native_test_native_code",
     ]
     set_sources_assignment_filter([])
     sources += [ "debug/proc_maps_linux_unittest.cc" ]
     set_sources_assignment_filter(sources_assignment_filter)
   }
+
+  if (is_win) {
+    # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+    cflags = [ "/wd4267" ]
+  }
 }
 
 if (is_android) {
   # GYP: //base.gyp:base_jni_headers
   generate_jni("base_jni_headers") {
     sources = [
       "android/java/src/org/chromium/base/ApplicationStatus.java",
       "android/java/src/org/chromium/base/BuildInfo.java",
       "android/java/src/org/chromium/base/CommandLine.java",
       "android/java/src/org/chromium/base/ContentUriUtils.java",
@@ skipping 90 matching lines @@
   # GYP: //base.gyp:base_unittests_apk
   unittest_apk("base_unittests_apk") {
     deps = [
       ":base_java",
       ":base_java_unittest_support",
       ":base_unittests",
     ]
     unittests_dep = ":base_unittests"
   }
 }