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

webrtc/libjingle/xmpp/BUILD.gn

Index: webrtc/libjingle/xmpp/BUILD.gn
diff --git a/webrtc/libjingle/xmpp/BUILD.gn b/webrtc/libjingle/xmpp/BUILD.gn
index 879d67236acdb31534b8241aee82ebb7bb43b78c..17a52fbaad4655ef5685f7845fa8076cb57339b3 100644
--- a/webrtc/libjingle/xmpp/BUILD.gn
+++ b/webrtc/libjingle/xmpp/BUILD.gn
@@ -139,9 +139,8 @@ rtc_static_library("rtc_xmpp") {
       "FEATURE_ENABLE_PSTN",
     ]
 
-    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" ]
     }
   }