GN: Fix windows clang errors. Attempt 2.

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 6e1b0ae407af4a6afacd0c63380461d5bf3818c2..826113dae4ac8b6d06d3e77be9bddc76c705b94f 100644
--- a/webrtc/system_wrappers/BUILD.gn
+++ b/webrtc/system_wrappers/BUILD.gn
@@ -133,6 +133,11 @@ source_set("system_wrappers") {
     cflags = [ "/wd4334" ]  # Ignore warning on shift operator promotion.
   }
 
+  if (is_clang) {
+    # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
+    configs -= [ "//build/config/clang:find_bad_constructs" ]
+  }
+
   deps += [ "../base:rtc_base_approved" ]
 }