Update Chomium's build files to work w/ latest GN binaries.

third_party/libjingle/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 
 # From third_party/libjingle/libjingle.gyp's target_defaults.
 config("jingle_unexported_configs") {
   defines = [
@@ skipping 18 matching lines @@
     "source",
     "../../testing/gtest/include",
     "../../third_party",
     "../../third_party/libyuv/include",
     "../../third_party/usrsctp",
   ]
 
   # Assumes libpeer is linked statically.
   defines += [ "LIBPEERCONNECTION_LIB=1" ]
 
-  if (is_win && cpu_arch == "x86") {
+  if (is_win && current_cpu == "x86") {
     defines += [ "_USE_32BIT_TIME_T" ]
   }
 
   if (use_openssl) {
     defines += [
       "SSL_USE_OPENSSL",
       "HAVE_OPENSSL_SSL_H",
     ]
   } else {
     defines += [
@@ skipping 518 matching lines @@
       "source/talk/app/webrtc/java/src/org/webrtc/StatsReport.java",
       "source/talk/app/webrtc/java/src/org/webrtc/SessionDescription.java",
       "source/talk/app/webrtc/java/src/org/webrtc/VideoCapturer.java",
       "source/talk/app/webrtc/java/src/org/webrtc/VideoRenderer.java",
       "source/talk/app/webrtc/java/src/org/webrtc/VideoSource.java",
       "source/talk/app/webrtc/java/src/org/webrtc/VideoTrack.java",
     ]
   }
 }  # enable_webrtc
 # TODO(GYP): Port libjingle.gyp's enable_webrtc condition block.