Enable size_t truncation warnings in webrtc.

Bug: chromium:167187
Change-Id: I57bc5609eade890520292697d2b033a485dd3234
No-Try: true
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227180
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34606}
diff --git a/webrtc.gni b/webrtc.gni
index 32417b4..184d13d 100644
--- a/webrtc.gni
+++ b/webrtc.gni
@@ -322,7 +322,6 @@
 # native code is built as part of Chromium.
 rtc_common_configs = [
   webrtc_root + ":common_config",
-  "//build/config/compiler:no_size_t_to_int_warning",
 ]
 
 if (is_mac || is_ios) {