Update existing uses of /wd4267 to use the GN config

third_party/smhasher/BUILD.gn

Index: third_party/smhasher/BUILD.gn
diff --git a/third_party/smhasher/BUILD.gn b/third_party/smhasher/BUILD.gn
index e1bbb5e33897e6aa16d23852059c4f3844a7df2a..9ca48620fd9e23b6c2cba80573504a685bcb539e 100644
--- a/third_party/smhasher/BUILD.gn
+++ b/third_party/smhasher/BUILD.gn
@@ -26,10 +26,9 @@ source_set("cityhash") {
     "src/City.h",
   ]
   configs -= [ "//build/config/compiler:chromium_code" ]
-  configs += [ "//build/config/compiler:no_chromium_code" ]
-
-  if (is_win) {
-    # TODO(jschuh): http://code.google.com/p/smhasher/issues/detail?id=19
-    cflags = [ "/wd4267" ]
-  }
+  configs += [
+    "//build/config/compiler:no_chromium_code",
+    # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+    "//build/config/compiler:no_size_t_to_int_warning",
+  ]
 }