Fix some sign-compare warnings in webrtc/api.

webrtc/api/BUILD.gn

 # Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("../build/webrtc.gni")
 import("//testing/test.gni")
 
 group("api") {
   deps = [
     ":libjingle_peerconnection",
   ]
 }
 
 config("libjingle_peerconnection_warnings_config") {
   # GN orders flags on a target before flags from configs. The default config
   # adds these flags so to cancel them out they need to come from a config and
   # cannot be on the target directly.
-  if (!is_win) {
-    cflags = [ "-Wno-sign-compare" ]
-    if (!is_clang) {
-      cflags += [ "-Wno-maybe-uninitialized" ]  # Only exists for GCC.
-    }
+  if (!is_win && !is_clang) {
+    cflags = [ "-Wno-maybe-uninitialized" ]  # Only exists for GCC.
   }
 }
 
 source_set("libjingle_peerconnection") {
   cflags = []
   sources = [
     "audiotrack.cc",
     "audiotrack.h",
     "datachannel.cc",
     "datachannel.h",
@@ skipping 66 matching lines @@
     "..:common_config",
     ":libjingle_peerconnection_warnings_config",
   ]
   public_configs = [ "..:common_inherited_config" ]
 
   if (is_clang) {
     # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
     configs -= [ "//build/config/clang:find_bad_constructs" ]
   }
 
-  if (is_win) {
-    cflags += [ "/wd4389" ]  # signed/unsigned mismatch.
-  }
-
   deps = [
     "../call",
     "../media",
     "../pc",
   ]
 
   if (rtc_use_quic) {
     sources += [
       "quicdatachannel.cc",
       "quicdatachannel.h",
@@ skipping 193 matching lines @@
       "../pc:rtc_pc",
       "../system_wrappers:metrics_default",
       "//testing/gmock",
     ]
 
     if (is_android) {
       deps += [ "//testing/android/native_test:native_test_support" ]
     }
   }
 }