GN: Exclude suppressions of Chromium Clang warnings for Chromium builds.

webrtc/system_wrappers/BUILD.gn

Index: webrtc/system_wrappers/BUILD.gn
diff --git a/webrtc/system_wrappers/BUILD.gn b/webrtc/system_wrappers/BUILD.gn
index 4dd85c24fcab2cde11884b49b477224557de09f7..5033caab9f08e0c32390f2aa2b2ad7fb27293711 100644
--- a/webrtc/system_wrappers/BUILD.gn
+++ b/webrtc/system_wrappers/BUILD.gn
@@ -208,9 +208,8 @@ if (rtc_include_tests) {
 
     configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
-    if (is_clang) {
-      # Suppress warnings from Chrome's Clang plugins.
-      # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
+    if (!build_with_chromium && is_clang) {
+      # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }