Update existing uses of /wd4267 to use the GN config

third_party/snappy/BUILD.gn

Index: third_party/snappy/BUILD.gn
diff --git a/third_party/snappy/BUILD.gn b/third_party/snappy/BUILD.gn
index 0f440a5556253e12cef20b3056606ce13b58b3db..199ba73d635c09a6efb53246b5e8ab1286e315b2 100644
--- a/third_party/snappy/BUILD.gn
+++ b/third_party/snappy/BUILD.gn
@@ -28,7 +28,11 @@ static_library("snappy") {
   ]
 
   configs -= [ "//build/config/compiler:chromium_code" ]
-  configs += [ "//build/config/compiler:no_chromium_code" ]
+  configs += [
+    "//build/config/compiler:no_chromium_code",
+    # https://code.google.com/p/snappy/issues/detail?id=75
+    "//build/config/compiler:no_size_t_to_int_warning",
+  ]
   public_configs = [ ":snappy_config" ]
 
   if (is_clang) {
@@ -36,9 +40,4 @@ static_library("snappy") {
     # https://code.google.com/p/snappy/issues/detail?id=70
     configs -= [ "//build/config/clang:extra_warnings" ]
   }
-
-  if (is_win) {
-    # https://code.google.com/p/snappy/issues/detail?id=75
-    cflags = [ "/wd4267" ]  # Conversion from size_t to 'type'.
-  }
 }